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Cancer Glossary

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Browse the glossary by selecting a letter or by entering a cancer-related term:

 Search  [guh-LACK-tuh-seal]
A clogged milk duct; a cyst filled with milk. It may occur in the breast during breast-feeding. See also cyst, duct.
See ductogram.
A pear-shaped organ under the liver that stores bile, a fluid made by the liver to help the body digest fat. The gallbladder releases bile into the small intestine during digestion.
Like familial adenomatous polyposis (FAP), Gardner syndrome is an inherited condition in which polyps develop in the colon at a young age and often lead to cancer. It can also cause non-cancerous tumors of the skin, soft connective tissue, and bones. See also APC gene, colon, familial adenomatous polyposis, inherited disease, polyp.
 Search  [GAS-trick]
Of or referring to the stomach.
 Search  [GAS-tro-EN-ter-AHL-uh-jist]
A doctor who specializes in diseases of the digestive (gastrointestinal) tract, such as the swallowing tube (esophagus), stomach, small intestine, and large intestine, as well as the liver, gallbladder, and pancreas. See also esophagus, gallbladder, large intestine, liver, pancreas, small intestine, stomach.
 Search  [GAS-tro-in-TEST-uh-nul STRO-muhl TOO-mers]
Often shortened to GISTs. Tumors that grow from special cells on the gastrointestinal wall known as the interstitial cells of Cajal. Most GISTs start in the stomach or small intestine. These tumors may or may not be cancer. GIST cancers are very different from other more common types of gastrointestinal tract cancers in treatment and outlook. See also gastrointestinal tract.
 Search  [GAS-tro-in-TEST-uh-nul trakt]
Also called the GI tract or the digestive tract. It’s made up of the organs and structures that process and prepare food to be used for energy, including the esophagus, stomach, small intestine, and large intestine. See also esophagus, large intestine, small intestine, stomach.
A piece of DNA (deoxyribonucleic acid) inside a cell that has the information to make a specific protein. Genes are responsible for traits passed on in families, such as hair color, eye color, and height, as well as susceptibility to certain diseases. See also deoxyribonucleic acid, mutation.
A type of treatment being studied in which defective genes would be replaced with normal ones. The new genes could be delivered into the cells by viruses or proteins. See also gene.
The process of counseling people who might have a gene that makes them more likely to develop cancer or another disease. The purpose of counseling is to explore what the genetic test results might mean, help people decide whether they wish to be tested, and support them before and after the test. See also gene, genetic counselor, genetic testing.
A specially trained health professional who helps people as they decide whether to get genetic testing, as they adjust to the test results, and as they consider whatever screening and preventive measures are best for them. They can also help a person understand what their results may mean for other family members. See also genetic counseling, genetic testing.
Tests that can be done to see if a person has certain gene changes known to increase the risk of cancer or other diseases. Such testing is not recommended for everyone, but for people with certain types of family history. Genetic counseling should be part of the genetic testing process. See also genetic counseling, hereditary cancer syndrome.
 Search  [JEE-nome]
The total DNA (deoxyribonucleic acid) and sometimes RNA (ribonucleic acid) in a single cell, representing all of the genetic information of the organism. The term genome can also refer to certain types of genetic material, such as that in the cell’s nucleus (nuclear genome) or mitochondria (mitochondrial genome). See also deoxyribonucleic acid, gene, ribonucleic acid.
The reproductive cells of the body, that is, eggs (ova) or sperm. See also ova, sperm.
 Search  [jess-TAY-shun-uhl]
Having to do with pregnancy.
 Search  [jess-TAY-shun-al tro-fo-BLAS-tick]
Often shortened to GTD. Also called hydatidiform moles (HI-duh-TID-ih-form) or molar pregnancies. A growth that starts in the cells that would normally develop into a placenta inside the womb (uterus) during pregnancy. Most of these rare tumors are not cancer. Compare to choriocarcinoma.
See gastrointestinal tract.
Cells or groups of cells that make and release substances to be used by the body or sent outside of it. The sweat glands and the pancreas are examples of organs that make and release substances. Note that swollen lymph nodes in the neck or armpit are often called “glands,” even though they actually are not. See also duct, endocrine glands, lymph node.
 Search  [GLAN-juh-luhr]
The cells in a gland that make substances. For example, glandular cells in the prostate make the milky fluid that becomes part of the semen.
 Search  [GLAN-juh-luhr TISH-oo]
Tissue that makes and secretes a substance. For instance, the lobules of the breast are glandular tissue because they make breast milk. See also lobules.
The head of the penis.
A number from 1 through 5, describing how how much the cancer cells look like normal prostate cells under the microscope based on the Gleason system. Those that look a lot like normal cells are graded 1, while those that look the least like normal cells are graded 5. See also Gleason score, grade, prostate.
The sum of the 2 Gleason grades used to classify prostate cancer based on how abnormal the cells look under the microscope. Because prostate cancers often have areas with different grades, a grade is assigned to the 2 areas that make up most of the cancer. These 2 grades are added to give a Gleason score between 2 and 10. This is used along with other information to stage the cancer. The higher the Gleason score, the faster the cancer is likely to grow and the more likely it is to spread beyond the prostate. See also Gleason grade, prostate, staging.
The grade of a cancer tells how abnormal its cells (or patterns of cells) look under the microscope. There are different grading systems for different types of cancers. Grading is done by a pathologist who looks at sample tissue from the biopsy. Cancers with higher grades (more abnormal-looking cells or patterns) tend to grow and spread more quickly and have a worse outlook. See also biopsy, pathologist, staging.
Often shortened to GVHD. The condition that results when the immune cells of a transplant (usually a bone marrow or other type of stem cell transplant) from a donor attack the tissues of the person receiving the transplant. See also allogeneic stem cell transplant, bone marrow, hematopoietic stem cell transplant, stem cells, umbilical cord blood transplant.
 Search  [GRAN-you-lo-SY-toe-PEE-nee-uh]
A lower-than-normal number of a type of white blood cell called a granulocyte (GRAN-you-lo-SITE). See also white blood cell.
 Search  [Gy]
A unit for measuring radiation transfer. See also radiation dose.
Naturally occurring proteins that help cells grow and divide. Some cancer cells are too sensitive to growth factors, which helps them grow quickly. See also epidermal growth factors.
 Search  [GWI-ack]
Substance used to test poop (stool) to see if it contains blood. See also fecal occult blood test.
 Search  [GUY-nuh-kuh-LA-jik on-KAHL-uh-jist]
A doctor who specializes in cancers of the female sex (reproductive) organs. See also cancer care team.
 Search  [GUY-nuh-KAHL-uh-jist]
A doctor who specializes in women’s health.
 Search  [GUY-nuh-ko-MAST-tee-uh]
Male breast enlargement, sometimes with breast tenderness; a possible side effect of some hormone treatments. See also hormone therapy.