Accessible – Tumors that can be approached using standard surgical techniques.
Acoustic neuroma/schwannoma (now called vestibular schwannoma) – This is usually a nonmalignant tumor of the 8th cranial nerve, which controls hearing and balance. These tumors tend to grow slowly and do not usually invade healthy tissue.
Adenoma – Most often a benign tumor that arises from a gland, for example, a pituitary adenoma.
Adjunctive treatment – Treatment given with the primary treatment to improve response rate; for example, if radiation is the primary treatment, chemotherapy is an adjunctive treatment if given while the patient is getting radiation therapy.
Adjuvant treatment – Treatment used following the primary treatment to cure, reduce, or control the cancer; for example, chemotherapy and radiation following cancer surgery are adjuvant therapies.
Agnosia – The loss of the ability to recognize objects, people, spatial relationships, shapes, or smells. This can result from a tumor in the parietal lobe.
Agraphia – A form of aphasia that is the loss of the ability to write. This is often a symptom of tumors in the parietal lobe.
Alkylating agent – A drug that interferes with a cell's DNA and discourages cell growth, for example, temozolomide (see Temodar).
Allele - one member of a pair or series of different forms of a gene.
Alopecia – Partial or complete loss of hair, which is often a side effect of radiation and certain chemotherapies.
Analgesic – Any medicine that treats pain.
Anemia – A deficiency of red blood cells. Symptoms include fatigue, shortness of breath, and weakness.
Angiogenesis – Blood vessel formation, particularly the growth of new blood vessels from surrounding tissue into tumor tissue. Angiogenesis is necessary for a tumor to grow larger and for metastases to grow at secondary sites.
Angiogenesis inhibitor (anti-angiogenesis) – A substance that may prevent the formation of new blood vessels. In anti-cancer therapy, an angiogenesis inhibitor prevents the growth of blood vessels from surrounding tissue into a solid tumor. Naturally occurring inhibitors are thrombospondin, endostatin, and angiostatin. Manipulating the genes involved in angiogenesis may be a way of controlling tumor growth.
Angiogram – A diagnostic procedure that visualizes blood vessels following the introduction of contrast material.
Anosmia – The absence of the sense of smell. This is a symptom common to tumors of the frontal lobe.
Anterior – Front or forward position.
Antibody – A protein that is produced by white blood cells (lymphocytes) as the immune system's response to an antigen. Antibodies are critical components of the immune system that circulate in the blood and bind to foreign antigens and tumor cells, thereby marking them for destruction by the immune system. Monoclonal antibodies (mAb) are laboratory-produced antibodies that can locate and bind to cancer cells throughout the body. Each recognizes a different protein on certain cancer cells.
Antiemetic – Any medication used to control vomiting.
Antigen – A foreign substance in the body that results in the production of antibodies.
Aphasia – The loss of the ability to speak or write and/or the loss of the ability to understand the speech or written words.
Apoptosis – Normal, timely cell death. Healthy cells live and die in predictable patterns to keep the numbers of cells in a body balanced. Abnormal cells lose the ability to sense the natural cues and go on needlessly reproducing. These extraneous cells eventually form a tumor.
Astrocytoma – These brain tumors arise from the star-shaped astrocyte cells, which are the supportive tissue of the brain.
Ataxia – An uncoordinated, clumsy walk.
Atonic – Having no muscle tone.
Basal ganglia – These are masses of nerve cells found deep within the cerebral hemispheres.
Basic research – Laboratory studies that explore the ways in which cells live, grow, and die. Basic research helps scientists discover and learn how brain tumors begin and what makes them grow.
Benign – A tumor that is not cancerous (or nonmalignant).
Bilateral – Occurring on both sides of the body.
Biologic response modifiers (BRM) – A substance, such as an angiogenesis inhibitor, used in adjuvant treatment that uses the body's natural defense mechanisms to inhibit the growth of a tumor.
Biologic therapy – Treatment that uses biologic response modifiers.
Biomarker (also called a tumor marker) – A substance sometimes found in the blood, other bodily fluids, or tissues. A high level of biomarker may mean that a certain type of cancer is present in the body.
Biopsy – A process whereby a small amount of tumor tissue is removed, usually through a thin needle, and microscopically examined to determine tumor type. A biopsy may be done during surgery.
Blastoma – Tumors, such as medulloblastoma or a glioblastoma multiforme, whose cells have embryonic characteristics.
Blood-brain barrier – A filtering mechanism made up of blood vessels and glial cells, which protects the brain by keeping out many harmful substances. Only certain types of chemotherapy can effectively cross this barrier to reach a brain tumor.
Bone marrow – The hollow center of bones that produces new blood cells, such as white and red blood cells and platelets.
Bone marrow transplant (also called a stem cell transplant) – For patients requiring high doses of chemotherapy, a side effect can be damage to the bone marrow, which produces new blood cells. After treatments are completed, doctors intravenously transplant healthy bone marrow or stem cells that were harvested prior to the treatment. The marrow begins producing a new supply of blood cells or the stem cells begin to mature into blood cells and reproduce. The types of transplants include an allogenic transplant, in which the transplant uses marrow harvested from a donor, and a peripheral stem cell rescue, in which stem cells from the blood are used instead of bone marrow cells. Transplants are now available to adults and children with medulloblastomas or glioblastomas.
Brain stem – The bottom portion of the brain that connects the cerebrum to the spinal cord. It contains the midbrain, pons, and medulla oblongata.
Brain stem glioma – A phrase used for glial tumors located in the brain stem. These are much more common in children than in adults.
Calcification – The deposit of calcium associated with certain types of tumors, such as meningiomas, astrocytomas, or oligodendrogliomas.
Cancer – A term used to describe more than 100 diseases characterized by uncontrolled, abnormal growth of cells. Cancerous tumors, or malignant tumors, can spread, or metastasize, locally into the lymph nodes or through the bloodstream to other parts of the body.
Carcinogen – Any contributing cause of cancer.
Carcinoma – A form of cancer that develops in the tissue or lining of the body, such as the breast, lung, skin, or uterus. More than 80% of all cancers are carcinomas.
Carcinogenesis – The process by which a normal cell becomes a cancerous cell.
Cardiovascular – A term that pertains to the heart and blood vessels.
Catheter – A thin, flexible tube used for the removal or insertion of fluids.
Cell kinetics – The time it takes for a tumor to attain a determined size.
Central nervous system (CNS) – A term that refers to the brain, cranial nerves, and spinal cord.
Cerebellopontine angle – This is the angle between the cerebellum and the pons. It is a common site for the growth of acoustic neuromas
Cerebellum – This is the second largest area of the brain, consisting of two hemispheres and located just above the brainstem, beneath the occipital lobes at the base of the skull. It connects the brain to the brain stem.
Cerebrospinal fluid (CSF) – A clear fluid made in the ventricles that circulates through the brain and spinal cord. By cushioning the brain and spinal cord, the fluid protects them from injury.
Cerebrum/cerebral hemispheres – This is the largest area of the brain and is located in the front portion of the forebrain. It is divided in to two hemispheres, which are further divided into four lobes: frontal, temporal, parietal, and occipital.
Chemotherapy (chemo) – Drugs that are used to stop or slow down the growth of cancer cells.
Chemoprevention – Use of drugs, vitamins, or other agents in an attempt to reduce the risk or delay the development or recurrence of cancer.
Chondroma – A rare, slow growing, nonmalignant tumor that often originates in the base of the skull, especially in the area near the pituitary gland.
Chondrosarcoma – The extremely rare, malignant form of chondroma. It is a locally invasive tumor, arising from bone and composed of cartilage.
Chordoma – These are usually benign, slow-growing tumors occurring at the base of the skull or at the end of the spine. They affect the adjacent cranial nerves and brain stem and are most common in younger and middle-aged adults.
Choroid plexus – A structure in the ventricles where cerebrospinal fluid is formed.
Choroid plexus papilloma – About 90% of choroid plexus tumors are papillomas, which are slow-growing and nonmalignant. Ten percent are choroid plexus carcinomas, which are malignant. This tumor occurs most often in children.
Chromosome – The structures in the cell nucleus that carry genes. Humans normally have 46 chromosomes.
Circumscribed – Tumors, often benign, that are localized and have a border, such as meningiomas or pituitary adenomas.
Clinical trials – Research studies done to determine whether new drugs, treatments, or vaccines are safe and effective. They are conducted in three phases:
- Phase I – In this phase, small groups of people are treated with a certain dose of a new agent that has been extensively studied in the laboratory. During the trial, the dose is increased group by group to find the highest dose that does not cause harmful side effects. Usually there is no control treatment for comparison. This process determines a safe, appropriate dose for use in Phase II.
- Phase II – This phase provides continued safety testing of a new agent, along with an evaluation of how well it works against a specific type of cancer. The new agent is given to groups of people and is usually compared with a standard treatment.
- Phase III – This phase answers research questions across the disease continuum and includes large numbers of participants so that the differences in effectiveness of the new agent can be evaluated. If the results of this phase merit further use of the new agent, the pharmaceutical company will usually submit a New Drug Application to the FDA.
CNS (central nervous system) lymphoma – A malignancy occurring in the central nervous system that arises from lymph cells (lymphocytes). Although multiple tumors may be visible on a scan, this type of brain cancer can be minutely seeded throughout the CNS.
Concave – Having a hollowed surface.
Congenital – Existing before or at birth.
Control group – A study is divided into two groups of people; one group gets the experimental treatment whereas the control group does not. Those not receiving the experimental treatment are collectively called the control group.
Convex – Having a rounded surface.
Cranial nerves – The 12 pairs of cranial nerves control functions such as taste, hearing, sensation in the face, smell, and swallowing.
Craniectomy – Surgery of the skull that involves removing a piece of bone, like a hatch, to gain access to the brain. The bone is not replaced at the time of surgery.
Craniopharyngioma – These brain tumors typically affect infants and children and are usually located near the pituitary gland. They often involve the optic nerve, the third ventricle, and the pituitary gland.
Craniotomy – Surgery of the skull that involves removing a piece of bone, like a hatch, to gain access to the brain. The bone is put back into place at the end of the surgery.
CT (computerized tomography or computerized axial tomography) scan – This specialized x-ray machine uses a computer to assemble many tiny x-rays to produce a clear, accurate picture of a thin slice of hard and soft tissues inside the body. A contrast dye is sometimes used to enhance the resulting image.
Cyst – A fluid-filled mass that is usually enclosed by a membrane.
Cytokines – Secreted proteins that are important for interactions between immune cells and that help orchestrate an immune response. Some cytokines suppress or stimulate the activity of immune cells. Others are cytotoxic. Cytokines can also be produced in the laboratory by recombinant DNA technology and given to patients to affect their immune responses.
Cytotoxic – Refers to the capacity to kill cells.
Debulk – A surgical procedure with the goal of decreasing the mass effect by removing dead tissue or a portion of the tumor.
Decompressive – A surgical procedure with the goal of lessening intracranial pressure by removing bone, tissue, or tumor.
Dendritic cell – An antigen-presenting cell named for its long arms, or dendrites. This type of cell is important for initiating and controlling the overall immune response and exists in many tissues. They are also sometimes described as "sentinels" that alert other immune cells to a possible attack.
Density – This is the amount of light or darkness in an area of a CT scan or MRI that reflects the compactness of the tissue
Dietary supplement – These are typically vitamins, but also include minerals, amino acids, and herbs.
Diffuse – Lacking a distinct border, spread out, not localized.
Diplopia – Double vision.
Double blind clinical trial – A clinical trial in which neither the doctor nor patient knows which drug is being given.
DNA (deoxyribonucleic acid) – The molecule that encodes genes, DNA is the repository of hereditary characteristics. It is a nucleic acid in the form of a linear, double-stranded DNA helix.
DNA methylation – A type of epigenetic mark. Changes in methylation affect gene expression. The more methylated a section of DNA, the less likely it is to be transcribed to RNA.
Drug resistance – The ability of a tumor cell to survive in the presence of drugs that are normally toxic.
Dura matter – The toughest, outermost meninges, or membrane, that covers the brain and spinal cord.
Dysphagia – Difficulty with swallowing or the inability to swallow. This can be a symptom of a tumor involving the lower brain stem.
Dysphasia – This is a language disorder that involves an inability to think of correct words or an inability to understand spoken or written words. This can be a symptom of tumors located in the cerebral hemisphere.
Dysplasia – The abnormal development of cells or tissue that can be a precursor of cancer.
Edema – Swelling caused by excess fluid. In the brain, edema can lead to increased intracranial pressure, causing drowsiness and headaches. Steroids are used to reduce edema.
EGFR (epidermal growth factor receptor) (also known as ErbB1 or HER1) – Protein found on the surface of some cells and to which epidermal growth factor binds, causing the cells to divide. EGFR is found at abnormally high levels on the surface of many types of cancer cells, and so these cells may divide excessively in the presence of epidermal growth factor.
Emesis – Vomiting.
Encapsulated – A tumor surrounded by a capsule and confined to a specific area.
Endocrine dysfunction – With brain tumors, this usually refers to a decrease or absence of hormone production by the pituitary gland.
Endpoint – What researchers measure to evaluate the results of a new treatment being tested in a clinical trial. Research teams establish the endpoints of a trial before it begins. An endpoint might be toxicity, tumor response, survival time, or quality of life.
Enhancement – This refers to a pattern seen on contrasted imaging studies, such as CT scans or MRIs, which appears due to the uptake of contrast dye by actively dividing cancer cells.
Enzyme – A protein that promotes essential functions in cell growth and metabolism.
Ependymoma – Brain tumors that come from the cells lining the ventricles of the brain and the center of the spinal cord. They are usually seen in children but occur in adults as well.
Epidemiological studies – Studies designed to examine disease in large groups of people. They are usually seeking patterns that can be used to prevent illness or detect its source.
Epigenetic – Having to do with the chemical attachments to DNA or the histone proteins around which it coils. Epigenetic marks change the pattern of genes expressed in a given cell or tissue by amplifying or muting the effect of the gene without altering the actual DNA sequence. Unlike mutations to DNA sequence, epigenetic modifications are often reversible. Tumor cells often contain epigenetic abnormalities.
Etiology – The study of the cause of a disease.
Familial – Tending to occur repeatedly among family members, but not considered genetic or inherited. Consequently, it can indicate a common environmental cause.
Fatigue – An intense feeling of being tired or drained of energy that can include a decreased ability to respond.
Focal – Limited to a specific area.
Gait – A pattern of walking.
Ganglia – A mass of nerve tissue or a group of nerve cell bodies.
Ganglioglioma – A rare, nonmalignant tumor that contains abnormal neurons and supportive cells.
Ganglioneuroma (also called a gangliocytoma) – This slow-growing, rare tumor contains glial cells and mature neurons. It can occur in either the brain or spinal cord.
Gene therapy – This treatment seeks to replace or repair defective or abnormal genes through the use of a biologic response modifier (BRM).
Generic drug – A drug not protected by a trademark and/or the scientific name versus the brand name.
Genetic – Inherited, or transferred, from parent to child via genes.
Gland – An organ that produces hormones that are released into the bloodstream, for example, the pituitary gland or the pineal gland.
Glial tissue (neuroglia) – Glial cells make up the supportive tissue of the brain. Glial cells can reproduce themselves and are the origin of the largest percentage of brain tumors.
Glioblastoma (GBM) – A high-grade astrocytoma containing necrotic, or dead, tumor cells. GBM tumors aggressively invade surrounding healthy tissue.
Glioma – A general name for tumors arising from the glial cells, the gluey/supportive tissue of the brain. There are many types of gliomas, including astrocytomas, oligodendrogliomas, and ependymomas.
Glucocorticosteroids (also called steroids) – Medications used to reduce brain swelling, such as Decadron (dexamethasone) and prednisone. Side effects can include weight gain, depression, mood swings, agitation, and difficulty sleeping.
Grade – The classification of a tumor according to its degree of aggressiveness and malignancy which can be helpful in predicting disease behavior and making treatment decisions. Brain tumors are graded on a scale of I to IV: Grade I refers to benign tumors (e.g., acoustic neuroma, menigioma), Grade II refers to low-grade tumors (e.g., low-grade oligodendroglioma), Grade III refers to intermediate-grade tumors (e.g., anaplastic oligodendroglioma), and Grade IV refers to the most malignant and aggressive brain tumors (e.g., glioblastoma).
Grand mal seizure (also called a tonic-clonic seizure) – A type of epileptic seizure characterized by a loss of consciousness and convulsions.
Gray matter – The part of the brain made up of nerve cells and blood vessels. The outer layer of the cerebrum and areas deep within the brain are made up of gray matter.
Growth factors – Nutrients in the body that help cells grow. Two growth factors now of interest to brain tumor researchers are VEGFR (vascular epithelial growth factor receptor), a growth factor involved in starting and stopping angiogenesis, and EGFR (epidermal growth factor receptor), found in very high quantities in most glioblastoma cells.
Hemangioblastoma (also called vascular tumors) – These nonmalignant and rare tumors develop from the blood vessels of the brain and spinal cord. The inherited condition Von-Hippel Lindau disease can predispose people to this tumor.
Hemianopsia – Loss of one-half of the field of vision.
Hemiparesis – Muscle weakness on one side of the body.
Hemiplegia – The complete paralysis of one side of the body.
Hereditary – Transferred from parent to child via genes.
Hormone – A chemical produced by a gland that is released into blood circulation and affects the functioning of other organs in the body.
Hydrocephalus – A condition arising from excessive cerebrospinal fluid in the brain (in lay terms, “water on the brain”).
Hyperthermia – The use of heat to kill tumor cells.
Hypotonic – Decreased muscle tone or limp muscles.
Hypothalamus – This structure makes up part of the wall of the third ventricle and is the base of the optic chasm.
Hypoxia – Lack of oxygen. Oxygen is needed for basic cell functions, it also makes a tumor sensitive to radiation. Researchers are looking at the effect of angiogenesis on oxygen levels, studying ways to cause hypoxia and trigger intentional cell death, and at the possibility of manipulating hypoxia-related genes.
Ictal – Refers to a seizure.
Immune system – The body's defense mechanism, which is composed of different types of white blood cells, and has the purpose of attacking and destroying harmful substances in the body.
Immunotherapy – The effectiveness of this treatment, with the goal of stimulating the body's immune system to fight tumors, is being explored in clinical trials. The premise is that, because brain tumor cells are foreign to the body, they should be managed by our normal immunologic defenses in a manner similar to a bacterial or viral infection. A “memory” of the foreign pathogen would be created and, consequently, if the immune system came in contact with a tumor cell again, it would recognize and destroy it.
In vitro – Occurs outside the body.
In vivo – Occurs inside the body.
Incidence – The number of new cases of a disease diagnosed within a given time frame.
Infiltrating – Refers to a tumor that invades normal surrounding tissue.
Interstitial radiation – The implantation of radioactive seeds directly in a tumor.
Intracavitary – Treatment delivered into the space, or cavity, created when the brain tumor was removed.
Intracellular – Occurs inside a cell.
Intracranial – Within the skull.
Intracranial pressure (ICP) – Pressure within the skull, which can be harmful when increased
Intramuscular (IM) – Into a muscle.
Intratumoral – Occurs inside a tumor.
Intravenous (IV) – Injection into a vein.
Invasive – Refers to a tumor that invades, or infiltrates, healthy tissue.
Ipsilateral – Affecting the same side.
Irradiation – Another name for radiation therapy that involves treatment using radioactive sources, for example, x-rays or radioactive iodine seeds.
Karyotyping – A technique for generating a “list” or profile of the genetic contents of a given piece of tissue.
Laser (light amplification by stimulated emission of radiation) – A surgical tool that destroys cells by vaporizing them with intense heat.
Laser capture microdissection – A new technique for examining tumor tissue. It allows specific cells to be removed from a sample of tissue for detailed study.
Lateral – On the side, such as the lateral ventricles.
Lethargy – An extreme lack of energy and vitality.
Leukocytes – White blood cells.
Li-Fraumeni syndrome – A rare, inherited cancer syndrome characterized by tumors at multiple sites. A mutation of the p53 tumor suppressor gene predisposes family members who inherit it to develop multiple cancers.
Ligand – A linking or binding molecule that binds to a specific complementary site on another molecule. For example, a growth factor is a ligand for its growth factor receptor.
Limbic system – In conjunction with the hypothalamus, the limbic system controls hunger, thirst, emotional reactions, and biological rhythms.
Linear accelerator (also called a linac) – An electrical apparatus that accelerates electrons to produce radiation for therapy and can also be used for radiosurgery. Three brand names of linear accelerators include ONCOR, CyberKnife®, and Novalis®.
Lipoma – A rare, nonmalignant tumor made of fat cells.
Lumbar puncture (LP) (also called a spinal tap) – A procedure involving the insertion of a thin needle into the lower spinal column to remove spinal fluid for testing and diagnosis or to deliver chemotherapy drugs to the central nervous system.
Macrophage – Immune response regulator that is phagocytic (ingests dying cells and debris), acts as an antigen-presenting cell, secretes cytokines, and can be cytotoxic.
Malignant – Tumors that are cancerous and tend to become progressively worse.
Medulla oblongata – The part of the brain stem that directly connects with the spinal cord.
Medulloblastoma – A form of primitive neuroectodermal tumor (PNET). They make up more than a quarter of childhood brain tumors and are one of the most common types seen in that age group.
Meninges – The three thin membranes that completely cover the brain and spinal cord. Cerebral spinal fluid flows between two of these membranes.
Meningioma – These tumors arise from the meninges; they tend to grow slowly and are not usually malignant. They are rare in children and are more common in women than men.
Metastasis – A malignant tumor that has spread from its site of origin to another part of the body, usually through blood vessels, the lymphatic system, or spinal fluid. A metatstatic (secondary) tumor contains cells that are like those in the original (primary) tumor.
Metastasize – To spread to another part of the body; for example, breast cancer can metastasize to the brain.
Metastatic brain tumor – A cancer that has spread from its primary site to the brain. Cancers of the lung, colon, kidney, breast, and skin (melanoma) can metastasize to brain tissue. Metastatic brain tumors can appear years after a primary cancer was diagnosed and treated.
Microglia – Tiny “scavenger” glial cells, found normally in the brain that play a role in the brain's immune functions. Of interest to researchers is the observation that microglia around a tumor appear to have their scavenger abilities turned off.
Midbrain – The portion of the brain between the pons and the cerebral hemispheres.
Mitosis – Cell division, resulting in the formation of two daughter cells that are genetically identical to the parent cell.
Mixed gliomas – These tumors contain more than one type of cell. Treatment focuses on the most malignant type of cell found in the tumor.
Modality – A method; for example, chemotherapy is a treatment modality.
Monoclonal antibodies (MAB) – A biologic response modifier considered to have a “homing” capacity; for example, chemicals or radiation tagged to the MAB might be delivered directly to tumor cells.
Morbidity – A disease or the incidence of disease within a population. Morbidity can also refer to adverse effects caused by a treatment.
Mouse model – A mouse breed genetically engineered to be missing particular genes. These mouse models are the closest science can come to duplicating the human tumor environment. A “spontaneous” mouse model is one engineered to grow a brain tumor without any tumor cells being introduced into its body.
MRI (magnetic resonance imaging) scan – A scan that uses a magnetic field, a computer, and radio waves to create an image that differentiates between normal and diseased tissue.
Necrosis – This simply means “dead tissue.” These dead cells are caused either by a lack of blood supply, because the tumor grows so fast that it outgrows its blood supply, or by radiation therapy. Necrosis is common with glioblastoma.
Neo-adjuvant treatment – A treatment, such as chemotherapy or radiation that is received before the primary treatment.
Neoplasm – A new growth of tissues or cells, such as a tumor, serving no physiological function; it can be malignant or nonmalignant.
Nervous System – The system of nerve tissue in the body, which includes the brain, brain stem, spinal cord, nerves, and ganglia.
Neuroblastoma – Cancer that arises in immature nerve cells and affects mostly infants and children.
Neurofibromatosis type 1 (NF1) – A rare genetic condition that causes brown spots and tumors on the skin, freckling in skin areas not exposed to the sun, tumors on the nerves, and developmental changes in the nervous system, muscles, bone, and skin.
Neurofibromatosis type 2 (NF2) (also called acoustic neurofibromatosis) – A genetic condition in which tumors form on the nerves of the inner ear and cause loss of hearing and balance. These tumors may also occur in the brain and on nerves in the skull and spinal cord, which may result in loss of speech, eye movement and the ability to swallow.
Neurologist – A physician who has undergone extra years of training to specialize in diagnosing and treating diseases of the nervous system.
Neuron – A nerve cell that conducts electrical signals.
Neuro-oncologist – A physician, usually a neurologist, who has received extra training to specialize in treating patients with brain cancers
Neuropsychiatrist – A psychiatrist who has undergone extra training in neurology to be able to diagnose and treat psychiatric problems caused by diseases of the nervous system. Because psychiatrists are medical doctors, they can order medical tests, such as CT scans or MRIs, and prescribe drugs.
Neuropsychological testing – Tests administered to assess the possible cognitive impact of tumor and treatment and to determine how the brain and nervous system are affecting thinking and behavior.
Neuropsychologist – A psychologist holding a Ph.D. who has undergone a year or more of extra training to be able to diagnose and treat psychological problems caused by diseases of the nervous system. They administer neuropsychological tests.
Neuropathy – A diseased condition involving the cranial or spinal nerves.
Neurosurgeon – A surgeon who has undergone extra years of training to specialize in surgery of the brain and spinal cord.
Nitrosourea – A group of chemotherapies that act similarly to the alkylating agents, such as CCNU and BCNU.
Nuclear medicine – The division of medicine that deals with the use of radioisotopes in diagnosis and treatment.
Observation – When a patient's condition is monitored closely, but treatment does not begin until symptoms appear or change, or there is a change in their MRI or CT scans.
Occupational therapist (OT) – A licensed healthcare provider who assists people in learning to manage the activities of daily living, such as dressing, cooking, and self-care. They can also help patients regain vocational skills.
Oligodendroglioma – A type of glioma that occurs most frequently in young and middle-aged adults. They are usually composed of oligodendrocyte cells.
Ommaya reservoir – A fluid reservoir that is implanted under the scalp with a catheter to a ventricle, allowing medication to be administered directly into the brain and CSF.
Oncogene – A mutated proto-oncogene that is locked into an active state and continuously stimulates unregulated cell growth and proliferation, leading to tumor development. The normal allele of an oncogene is called a proto-oncogene.
Oncogenesis (also called tumorigenesis) – The process by which normal cells turn cancerous. A sequence of cytological, genetic, and cellular changes causes the development of tumors.
Oncology – The science pertaining to, and study of, malignant tumors and cancer.
Ophthalmoscope – A handheld instrument used by a healthcare provider to examine the inside of the eye.
Optic chiasm – This is the area under the hypothalamus where the optic nerves cross each other.
Optic nerve glioma – This is a type of glioma arising from the optic nerve.
Oral – Relating to the mouth.
Orphan disease – A disease with an annual incidence of less than 200,000 in the United States.
p16, p53, etc. – The "p" preceding a number indicates this is a gene. p16 and p53 are two of the many genes known to be altered in brain tumors. Studies underway are looking for abnormal genes, measuring the substances given off by those genes, looking at the impact of gene by-products on the patient's future, and studying how abnormal genes interact with the genes and proteins around them.
Palliative care/treatment – Treatment aimed at the relief of pain and symptoms of disease. Palliative care is not intended to cure the disease.
Palsy – Paralysis, especially with involuntary tremors.
Papilledema – Swelling of the optic nerve.
Paralysis – The loss of voluntary motor or muscle movement due to an injury or disease of the nervous system.
Paresthesia – Abnormal sensations, such as burning or tingling.
Pathologist – A physician who has undergone extra years of training to recognize the causes, processes, and effects of disease. A pathologist microscopically examines tissue taken from a tumor to determine the type of tumor.
Permeable – Allows the passing through of substances; for example, the blood-brain barrier is selectively permeable.
PET (positron emission tomography) scan – This is a scanning device that uses a low-dose radioactive glucose to measure brain metabolic activity.
Petit mal seizure (also called an absence seizure) – This is a type of epileptic seizure characterized by a brief impairment of consciousness.
Photodynamic radiation therapy (PRT) – Prior to a surgical procedure, a light-sensitive drug is injected through a vein and concentrates in the tumor. During the procedure, a special light is activated and the drug then kills tumor cells.
Physical therapist (PT) – A licensed healthcare provider who assists people in regaining muscle function.
Pineal tumors – These very rare tumors represent less than 1% of all primary brain tumors. They arise from the pineal gland, which is a small structure deep in the middle of the brain.
Pituitary gland – This is a small double-lobed gland at the base of the brain that affects hormonal function.
Pituitary tumors – These tumors are usually nonmalignant. Because the pituitary gland secretes hormones, some pituitary tumors mimic this and may flood the body with abnormal amounts of hormones.
Placebo – An inactive and harmless substance that has no biological effect.
Platelets – The cells in blood that help clotting; consequently, too few platelets can result in severe bleeding. Because chemotherapy can reduce the number of platelets the body produces, platelets are monitored during this treatment.
Pons – A bridge of nerve fibers forming part of the brain stem.
Positron Emission Tomography – See PET scan.
Posterior – The rear.
Posterior fossa – The shallow hollow of the occipital bone in which the cerebellum and fourth ventricle are located.
Potentiate – To make more effective.
Preclinical testing – A process in which scientists test promising new agents in the laboratory and in animal models. This determines whether agents have an anti-cancer effect and are safely tolerated in animals. If a drug proves promising in the lab, the sponsor applies for FDA approval to test it in clinical trials involving people.
Primary therapy/treatment – The initial treatment.
Primitive neuroectodermal tumor (PNET) – An aggressively malignant and fast-growing tumor most often occurring in children and young adults. Medulloblastomas are a form of this tumor.
Prognosis – The chances of recovery and survival.
Proliferate – To grow by cell production.
Prophylactic – Treatment that is preventative.
Proteome – All of the proteins encoded by the genome and produced by a person's cells and tissues.
Proteomics – The study of the network of proteins, including identifying the proteins made in a cell or tissue, deciphering how these proteins interact, and determining their three-dimensional structures to find sites where drugs could interfere with their functions.
Protocol – A written treatment plan for a clinical trial that states the goals of the study, the tests and treatments that will take place, and the rationale behind each part of the study.
Quality of life – Overall enjoyment of life. Often used when discussing or considering treatment options to refer to the patient's level of comfort, sense of well-being, and ability to perform various tasks.
Radiation therapy/radiotherapy – The use of radiation energy to interfere with tumor growth. Radiation may come from a machine outside the body or from radioisotopes, which can be placed in or near the tumor. This is called internal radiation therapy, implant radiation, interstitial radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance, such as a radiolabeled antibody, that circulates through the body.
Radiation necrosis – Cell death due to radiation. Radiation necrosis is usually the result of higher doses of radiation and is more common with aggressive tumors.
Radioresistant – Resistant to radiation therapy.
Radiosensitive – Responsive to radiation therapy.
Radiosurgery – See Stereotactic radiosurgery.
Randomized clinical trial – A study in which each patient is selected by chance to receive one of the various treatment options to compare different treatments. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively.
Recurrence – The return of symptoms or a tumor.
Red blood cells – These cells carry oxygen throughout the body. If too few are produced, anemia can result. Because chemotherapy can reduce the number of red blood cells, they are monitored during treatment.
Rehabilitation – Often with the assistance of trained health care professionals, such as physical therapists, this is the return of function after illness or injury.
Remission – The disappearance of symptoms or a tumor.
Resection – The surgical removal of tissue or a tumor. The goal of surgery is usually complete resection of the tumor.
Residual tumor – The tumor remaining after resection.
RNA (ribonucleic acid) – Single-stranded nucleic acid containing ribose instead of deoxyribose. Messenger RNA (mRNA) is formed on and complementary to its DNA template and directs the translation of a gene into a protein.
Salvage treatment – Treatment given when all standard treatments have been exhausted.
Sarcoma – This is a tumor that arises from connective tissue, bone, cartilage, or striated muscle and that spreads by infiltrating surrounding tissue or through the blood stream.
Schwannomas (also called vestibular schwannomas or acoustic neuromas) – These tumors arise from myelin, the sheath that protects nerve cells, and are usually nonmalignant. Schwannomas often affect the 8th cranial nerve, which governs balance and hearing.
Second-line treatment – Treatment that is given after the cancer has not responded to a first course of therapy or after a patient ceases first-line therapy.
Seizures – These are sometimes a symptom of a brain tumor and result from abnormal electrical activity within the brain. Seizures may cause convulsions, loss of consciousness, or sensory distortions.
Sella (sella turcica) – This is the hollowed extension of the sphenoid bone that contains the pituitary gland.
Shunt – A surgically implanted tube that is used to relieve increased intracranial pressure.
Signal transduction – Refers to the series of steps occurring in cell cytoplasm after a receptor binds its ligand to communicate, or transduce, the signal to the cell nucleus. The signal of an activated receptor is carried through cells by various intracellular messengers and enzymes. Often the signal is sent to the nucleus, where genes are turned on or off to change the cell's function.
Signaling pathways – The molecular steps preceding and following an action by any gene or gene byproduct. Researchers may study the signaling pathways of proteins or enzymes found in elevated quantities in brain tumors. These studies look at what precedes and what happens after the release of these substances.
Single blind clinical trial – A study in which the doctor, but not the patient, knows which treatment is being given.
Social worker – A licensed practitioner who provides counseling, case management, and important resources to brain tumor patients and their families. Social workers also help patients communicate with their doctors and navigate the medical system.
Spasticity – Increased involuntary muscle contraction.
Spinal cord – A bundle of nerve fibers that extends down from the brain stem and continues to hollow center of the spinal column.
Spinal fluid - See Cerebrospinal Fluid (CSF).
Spinal tap - See Lumbar puncture (LP)
Stable disease – Classification of a tumor in which there is no significant change in size. A tumor may shrink, but not enough to be categorized as a partial response (a tumor reduction greater than 50%), or a tumor may increase in size, but not enough to be considered progressive disease (tumor growth greater than 20%).
Standard treatment – Unlike investigational treatment, this has been proven to be effective.
Stem cells – New cells capable of developing into one of a variety of cell types. Most cells have a specific function, such as heart cells or brain cells, but stem cells are blank, immature cells that can develop into virtually any kind of cell in the human body. They are the focus of research because it is hypothesized that scientists could theoretically grow stem cells to repair damaged cells. It is unlikely that this will be a treatment for years because it is still unknown how to customize blank stem cells and turn them into cells with a specific function.
Stem cell transplant – See Bone marrow transplant.
Stereotactic – Describes a surgery or radiation therapy that is directed by a scanning device for precise positioning in a three-dimensional space.
Stereotactic needle biopsy – A biopsy done by using the stereotactic guidance of computers, such as MRI or CT scanning procedures.
Stereotactic radiation – A treatment in which a rigid head frame is attached to the skull and a single high dose of radiation is delivered with precision to the tumor. By using a high dose of focused beams to target a tumor, normal brain tissue is spared from injury. It is used with tumors of smaller dimensions. Examples of stereotactic radiation include linac radiosurgery and Gamma Knife® radiosurgery.
Stereotactic surgery – Using a computer, a three-dimensional image is created to provide precise information about a tumor's location and position within the brain. This is used as a map for surgeons to rehearse the actual surgery before it occurs and to localize the target during surgery.
Steroids – See Glucocorticosteroids.
Stimuli – Agents or actions that cause a physiological response.
Stomatitis – Inflammation of the mucous membrane that lines the mouth. This is sometimes a side effect of chemotherapy or radiation.
Strabismus – Crossed eyes due to an imbalance of the eye muscles.
Study arm – A treatment offered in a clinical trial.
Subcutaneous – Beneath the skin.
Superficial – Close to the surface.
Systemic – Circulating throughout the body.
T cells – White blood cells that regulate immune response by attacking virus-infected cells, foreign cells, and cancer cells. Helper T cells enhance the response of other effector cells by secreting cytokines. Cytotoxic T cells can directly kill virus-infected cells and tumor cells.
Targeted therapy – Treatment that uses drugs or other substances to identify and attack specific cancer cells, while limiting the effect on normal cells.
Temodar – The U.S. brand name for temozolomide, an oral chemotherapy drug for brain tumors that is one of the few drugs that can penetrate the blood-brain barrier.
Tentorium – A flap of the meninges that separates the cerebral hemispheres from the brain structures in the posterior fossa.
Tinnitus – A buzzing or ringing in the ear that can be a symptom of a tumor of the acoustic nerve.
Toxicity – Harmful side effects from an agent being tested.
Transformation – Process by which a normal cell undergoes a series of changes that cause it to become cancerous.
Translational research – Studies that provide the bridge between basic research and human testing. Translational research provides the data to support the opening of a clinical trial or additional scientific evidence as to how a substance in a clinical trial works.
Transsphenoidal surgery – This is a common surgical procedure used to remove pituitary adenomas or craniopharyngiomas that involves accessing the sphenoid sinus through the nose.
Tumor – An abnormal growth that can be benign or malignant.
Tumor grading – See Grade.
Tumor marker – See Biomarker.
Tumor progression/promotion – The process of a tumor's growing larger or metastasizing.
Tumor suppressor gene – A gene that blocks or suppresses the formation of tumors by inhibiting excessive cell proliferation. Mutations that permanently disable tumor suppressor genes can cause a cell to grow uncontrollably, leading to tumor development.
Ultrasound – A device that visualizes structures in the body by recording the reflections of sound waves directed into tissues.
Undifferentiated – An immature or primitive cell that has a nonspecific appearance and functions poorly.
Vascular – Relating to blood vessels.
Vascularity – The blood supply of a tumor.
Vector – A carrier for delivering therapy to the cells of a tumor.
VEGF (vascular endothelial growth factor) – Protein secreted by oxygen-deprived cells, such as cancerous cells. VEGF stimulates new blood vessel formation, or angiogenesis, by binding to specific receptors on nearby blood vessels, encouraging new blood vessels to form.
Ventricles – The four cavities of the brain that contain the choroid plexus, which produces cerebrospinal fluid.
Vertigo – Dizziness; a common symptom of tumors of the acoustic nerve.
Wafer implants (also called polymer wafer implants) – A dissolvable wafer saturated with an anti-cancer drug, that is placed in the remaining cavity after a tumor is removed.
White blood cells – The body's primary defense against infections. While people are on chemotherapy, these are monitored because, if too few are produced, infection can result.
White matter – Brain tissue composed of nerve cell fibers that carry information between the nerve cells in the brain and spinal cord.