Cancer: a term for diseases in which abnormal cells divide without control and can invade nearby tissues. “Malignant” cells can also spread to other parts of the body through the blood and “lymph systems.” (NCI1) A disease of multicellular organisms… characterized by uncontrolled "cell division.” (Brooker, 288)

Caused by “gene” “mutations” that lead to uncontrolled cell growth. (Brooker, 277) In addition to inherited DNA differences, we can also accumulate defects in the DNA code of a single cell. Many cancers originate in this way. (Batiza, 19) Cancer grows out of normal cells in the body. Normal cells multiply when the body needs them, and die when the body doesn't need them. Cancer appears to occur when the growth of cells in the body is out of control and cells divide too quickly. It can also occur when cells forget how to die. (PubMedHealth2) Also referred to as ‘malignancy.’


Anaplasia: reversion to a less differentiated structure. (Lawrence) Loss of structural "differentiation" and useful function. (MeSH) Loss of normal cell characteristics, which may be to such a degree that it is impossible to define the origin of the cells. Typical of rapidly growing tumors malignant tumors which are describes as 'anaplastic.' (OxfordMe)

Benign: tumors that do not become invasive (Lawrence) Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. (NCI1) Benign tumors may nonetheless, cause... mortality by compressing or obstructing vital structures. (OxfordMed) Also referred to as ‘nonmalignant.’

Cancer Subtype: describes the smaller groups that a type of cancer can be divided into, based on certain characteristics of the cancer cells. These characteristics include how the cancer cells look under a microscope and whether there are certain substances in or on the cells or certain changes to the DNA of the cells. It is important to know the subtype of a cancer in order to plan treatment and determine prognosis. (NCI1)

Cancer Treatments: tests and treatments target cancer cells now while sparing healthy ones, thanks to genetic discoveries. Increasingly, cancer diagnosis utilizes “DNA microarrays” that scan the “genome” for cancer-associated mutations as well as gene expression patterns. (Lewis, 366-377)

Cancer Surgery: a procedure to remove or repair a part of the body or to find out whether disease is present. An operation. (NCI1) The oldest cancer treatment. Prevents invasiveness by removing the tumor. (Lewis, 367)

Cancer Vaccine(s): a type of vaccine that is usually made from a patient’s own tumor cells or from substances taken from tumor cells. A cancer vaccine may help the immune system kill cancer cells. (NCI1) Vaccines or candidate vaccines designed to prevent or treat cancer. Vaccines are produced using the patient's own whole tumor cells as the source of "antigens," or using tumor-specific antigens. (MeSH) Also referred to as ‘cancer treatment vaccine.’

Chemotherapy: a treatment with drugs that kill cancer cells. (NCI1) Chemotherapy may be used to cure the cancer, prevent the cancer from spreading, and/or relieve symptoms when the cancer cannot be cured. (PubMedHealth2) Destroys rapidly dividing cells. Helps 90% of children with ‘lymphoblastic’  “leukemia.” Treatments also affect healthy cells causing side effects of nausea, hair loss, great fatigue, and susceptibility to infection. (Lewis, 367)

Colony Stimulating Factors: a group of substances that are produced in the bone marrow and stimulate the production of specific blood cells. (Oxford) A "cytokine" that stimulates production of "macrophages" from... "precursor cells." (Lawrence) Replenish "bone marrow." (Lewis, 366)

Gleevec: used alone or together with other medicines to treat different types of cancer or bone marrow conditions. It prevents or stops the growth of cancer cells. (PubMedHealth2) “Cytotoxic” drug that works by inhibiting “enzymes” that are active in some types of cancer cells. (OxfordMed) Standard treatment for “chronic myelogenous leukemia.” Treats (the) ‘fusion gene’ from a “Philadelphia chromosome.” (Lewis, 358) Editor’s note - generic name ‘imatinib.’

Radiation Therapy: the use of high-energy “radiation” from “x-rays,” "gamma rays," “neutrons,”  “protons,” and other sources to kill cancer cells and shrink tumors. (NCI1) Because radiation is most harmful to quickly growing cells, radiation therapy damages cancer cells more than normal cells. This prevents the cancer cells from growing and dividing, and leads to cell death. Used to fight many types of cancer. Sometimes, radiation is the only treatment needed. It may also be used to shrink a tumor as much as possible before surgery, help prevent the cancer from coming back after surgery or chemotherapy, or relieve symptoms caused by a tumor (PubMedHealth2) Also referred to as ‘radiotherapy’ and ‘irradiation.’

External-Beam Radiation Therapy: a type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. (NCI1) Also referred to as ‘external radiation therapy.’

X-Ray Therapy: a type of radiation therapy that uses high-energy radiation from x-rays to kill cancer cells and shrink tumors.

Internal Radiation: (uses) radioactive material placed in the body near cancer cells. (NCI1) Editor’s note - example, ‘radioactive seed placement therapy.’

Systemic Radiotherapy: uses a radioactive substance, such as a radio-labeled antibody, that travels in the blood to tissues throughout the body. (NCI1)

Retinoic Acid: vitamin A derivative, used experimentally to induce differentiation in tumor cells. It is also a natural "morphogen" in "vertebrate" development. (Lawrence) Stimulates cells to regain specialized characteristics. For example - drugs that Inhibit "telomerase" which prevents cells from elongating their “telomeres” and continually dividing. (Lewis, 367)

Cancer Types: there are several main types of cancer including “carcinomas,” “sarcomas,” “multiple myelomas,” “central nervous system" cancers, and “lymphoma.” (NCI1) Cancer can develop in almost any "organ" or "tissue," such as the lung, colon, breast, skin, bones, or nerve tissue. (PubMedHealth2)

Bladder Cancer: cancer that forms in tissues of the bladder. Most bladder cancers are transitional cell carcinomas (cancer that begins in cells that normally make up the inner lining of the bladder). Other types include 'squamous cell carcinoma' (cancer that begins in thin, flat cells) and 'adenocarcinoma' (cancer that begins in cells that make and release mucus and other fluids). The cells that form squamous cell carcinoma and adenocarcinoma develop in the inner lining of the bladder as a result of chronic irritation and inflammation. (NCI1) In the United States, bladder cancers usually start from the cells lining the bladder. These tumors are classified based on the way they grow. ‘Papillary tumors’ have a wart-like appearance and are attached to a stalk. ‘Nonpapillary ('sessile') tumors’ are flat. They are much less common. However, they are more invasive and have a worse outcome. (PubMedHealth2) The exact cause of bladder cancer is uncertain. (Risk factors include) cigarette smoking, chemical exposure at work, chemotherapy, radiation treatment, and bladder infection. (PubMedHealth2)

Breast Cancer: cancer that forms in tissues of the breast. The most common type of breast cancer is ‘ductal carcinoma,’ which begins in the lining of the thin tubes that carry milk from the “lobules” of the breast to the nipple. Another type of breast cancer is ‘lobular carcinoma,’ which begins in the milk glands of the breast. ‘Invasive' breast cancer is breast cancer that has spread from where it began in the breast ducts to surrounding normal tissue. Breast cancer occurs in both men and women, although male breast cancer is rare. (NCI1) ‘BRCA1’ and ‘BRCA2’ are the first two “genes” found to be associated with inherited forms of breast cancer. Both genes normally act as “tumor suppressors,” meaning that they help regulate cell division. When these genes are rendered inactive due to mutation, uncontrolled cell growth results, leading to breast cancer. Women with mutations in either gene have a much higher risk for developing breast cancer than women without mutations in the genes. (NHGRI) Many breast cancers are sensitive to the hormone "estrogen." This means that estrogen causes the breast cancer tumor to grow. Such cancers have estrogen receptors on the surface of their cells. They are called ‘estrogen receptor-positive’ cancer or ‘ER-positive cancer.' Some women have ‘HER2-positive’ breast cancer. ‘HER2’ refers to a gene that helps cells grow, divide, and repair themselves. When cells have too many copies of this gene, they grow faster. (PubMedHealth2) (Actionable) risk factors include: alcohol use, obesity, and radiation. (Non-actionable) risk factors include age and gender, family history of breast cancer, and genetic mutations (in BRCA1 and BRCA2). (PubMedHealth2)

Carcinoma: cancer that begins in the skin or in tissues that line or cover internal organs. (NCI13) Cancers of “epithelial” cells. Most cancers in the lung are carcinomas. (Brooker, 295) A malignant (abnormal) cell growth made up of “epithelial” cells. Tends to infiltrate the surrounding tissues and give rise to metastases. It is often wrongly used as a synonym for cancer. (MeSH)

Central Nervous System Cancer: cancers that begin in the tissues of the brain and "spinal cord." Representative examples include 'anaplastic astrocytoma,' 'glioblastoma,' 'anaplastic (malignant) meningioma,' "lymphoma," and "metastatic" carcinoma from another anatomic site. (NCIt)

Hereditary Nonpolyposis Colon Cancer (HHPCC): colon, or 'colorectal,' cancer is cancer that starts in the large intestine (colon) or the end of the colon. (PubMedHealth2) Affects 1 in 200 people, and mutations in any of at least 7 genes can cause it. Accounts for 3% of newly diagnosed colorectal cancers. “Penetrance” is about 45% by age 70 - considered a high cancer risk. Genetic testing in those newly diagnosed is advised because if they have a mutation, their relatives can be tested. If relatives test positive, frequent 'colonoscopies' can detect disease early, at a more treatable stage. (Lewis, 229)

Leukemia: cancer that starts in blood-forming tissue, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. (NCI1) The term leukemia means ‘white blood.’ Leukemia leads to an uncontrolled increase in the number of white blood cells. The cancerous cells prevent healthy red cells, "platelets," and mature white cells from being made. The cancer cells can spread to the bloodstream and lymph nodes. They can also travel to the brain and spinal cord and other parts of the body. Leukemias are divided into two major types: ‘acute,’ which progresses quickly, and ‘chronic,’ which progresses more slowly. (PubMedHealth2)

Chronic Myelogenous Leukemia (CML): a slowly progressing disease in which too many white blood cells (not lymphocytes) are made in the bone marrow. (NCI1) A cancer that starts inside bone marrow. CML causes an uncontrolled growth of immature cells that make a certain type of white blood cell called ‘myeloid cells.’ The diseased cells build up in the bone marrow and blood. Cause of CML is often related to an abnormal chromosome called the “Philadelphia chromosome.” Radiation exposure can increase the risk of developing CML. (PubMedHealth2) Also referred to as ‘chronic granulocytic leukemia,’ and  ‘chronic myeloid leukemia.’

Lung Cancer: cancer that forms in tissues of the lung, usually in the cells lining air passages. The two main types are ‘small cell lung cancer’ and ‘non-small cell lung cancer.’ These types are diagnosed based on how the cells look under a microscope. (NCI1) If the cancer started somewhere else in the body and spread to the lungs, it is called ‘metastatic cancer to the lung.’ Lung cancer is the deadliest type of cancer for both men and women. Each year, more people die of lung cancer than of breast, colon, and prostate cancers combined. Lung cancer is more common in older adults. It is rare in people under age 45. Cigarette smoking is the leading cause of lung cancer. (PubMedHealth2)

Lymphoma: cancer that begins in cells of the "immune system." There are two basic categories of lymphomas. One kind is ‘Hodgkin lymphoma,’ which is marked by the presence of a type of cell called the ‘Reed-Sternberg’ cell. The other category is ‘non-Hodgkin lymphomas,’ which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an slow-growing course and those that have an aggressive course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer. (NCI1)

Multiple Myelomas: (like lymphoma), cancers that begin in the cells of the immune system. (NCI1) Start in the ‘plasma cells’ in bone marrow. With multiple myeloma, plasma cells grow out of control in the bone marrow and form tumors in the areas of solid bone. The growth of these bone tumors weakens the solid bones and also makes it harder for the bone marrow to make healthy blood cells and platelets. The exact cause of multiple myeloma is not clear. Multiple myeloma most commonly causes a low 'red blood cell count' (anemia), which can lead to fatigue and shortness of breath. It can also cause low 'white blood cell count,' which makes (an individual) more likely to get infections. Multiple myeloma also causes low platelet count, which can lead to abnormal bleeding. (PubMedHealth2)

Prostate Cancer: a disease characterized by uncontrolled cell growth in the "prostate gland," which is part of the male reproductive system. Prostate cancer generally affects men over the age of 50. It is responsible for more deaths among men than any other cancer except lung cancer. (NHGRI)

Sarcoma: cancer that begins in "bone," "cartilage," "fat," "muscle," "blood vessels," or other connective or supportive tissue. (NCI1) (Abnormal growth of) connective tissue formed by proliferation of "mesodermal" cells. It is usually highly malignant. (MeSH)

Stomach Cancer: cancer that forms in tissues lining the stomach. (NCI4) Several types of cancer can occur in the stomach. The most common type is called ‘adenocarcinoma.’ It starts from one of the common cell types found in the lining of the stomach. (PubMedHealth2) Also referred to as ‘gastric cancer.

Carcinogenesis: the process by which normal cells are transformed into cancer cells. (NCI1) The origin, production or development of cancer through “genotypic” and “phenotypic” changes which upset the normal balance between cell proliferation and cell death. Carcinogenesis generally requires a constellation of steps, which may occur quickly or over a period of many years. (MeSH)

Invasion: ability of (tumors) to infiltrate and actively destroy surrounding tissue. (MeSH) Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. (NCI1) Also referred to as 'invasive cancer' and ‘infiltrating cancer.’

Malignant: (tumors) that have become invasive and can spread to other parts of the body. (Lawrence) Cancerous. Malignant cells can invade and destroy nearby tissue and spread. (NCI1) Cancerous cells that have the ability to spread to other sites in the body ("metastasize") or to invade and destroy tissues. Malignant cells tend to have fast, uncontrolled growth due to changes in their genetic makeup. Malignant cells that are resistant to treatment may return after all detectable traces of them have been removed or destroyed. (PubMedHealth2)

Metastasis: the transfer of a (tumor) from one organ or part of the body to another, remote from the primary site. (MeSH) The migration of cancer cells to colonize tissues and organs other than those in which they originated. (Lawrence) The spread of cancer. A tumor formed by cells that have spread, is called a ‘metastatic tumor.’ The metastatic tumor contains cells that are like those in the “primary tumor.” (NCI1) Verb - 'metastasize.' Adjective - 'metastatic.'

Oncogene: a gene, one or more forms of which is associated with cancer. Many oncogenes are involved, directly or indirectly, in controlling the rate of cell growth. (HGPIA) A mutated form of a gene involved in normal cell growth. Oncogenes may cause the growth of cancer cells. Mutations in genes that become oncogenes can be inherited or caused by being exposed to substances in the environment that cause cancer. (NIC3) Causes cancer when inappropriately activated. May be the result of a mutation. May be the result of a change in expression of the (normal) gene. Cancers associated with viral infections may begin when "proto-oncogenes" are mistakenly activated with "antibody" genes. Can become an oncogene when it is placed next to a gene that boosts its expression. (Lewis, 357) Some oncogenes work like putting your foot down on the accelerator of a car, pushing a cell to divide. Other oncogenes work like removing your foot from the brake while parked on a hill, also causing the cell to divide. (NHGRI)

Precancerous: a term used to describe a condition that may (or is likely to) become cancer. (NCI1) A nonmalignant condition that is known to become malignant if left untreated. (OxfordMed) Also referred to as ‘premalignant.’

Precancerous Dermatitis: a skin disease marked by scaly or thickened patches on the skin and often caused by prolonged exposure to arsenic. The patches often occur on sun-exposed areas of the skin and in older white men. These patches may become malignant. (NCI1) Also referred to as ‘Bowen disease’ and ‘precancerous dermatosis.’

Proto-Oncogene: a gene involved in normal cell growth. Mutations (changes) in a proto-oncogene may cause it to become an oncogene, which can cause the growth of cancer cells. (NIC3) Gene that normally triggers cell division when it is appropriate. (Lewis, 357) In their normal, un-mutated state, oncogenes are called proto-oncogenes, and they play roles in the regulation of cell division. (NHGRI)

Tumor: a growth resulting from the abnormal proliferation of cells. (Lawrence) Any abnormal swelling in or on a part of the body. An abnormal growth of tissue. (OxfordMed) An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). (NCI1) New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms. (MeSH) Also referred to as ‘neoplasm.’

Primary Tumor: a term used to describe the original, or first, tumor in the body. Cancer cells from a primary tumor may spread to other parts of the body and form new, or 'secondary tumors.' This is called metastasis. These secondary tumors are the same type of cancer as the primary tumor. (NCI1) Also referred to as ‘primary cancer.’

Tumor Suppressor Genes: ones that normally function to put the brakes on the growth of cells. (Batiza, 84) Normally inhibit expression of genes involved in activities that turn a cell cancerous. Cause cancer when they are deleted or inactivated. (Lewis, 360) The role of a normal (‘non mutant’) tumor-suppressor gene is to prevent cancerous growth. (Brooker, 293)