Glossary of Terms

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Programmed cell death. Apoptosis is controlled by genes that cause a cell to die at a specific time, e.g., when DNA is damaged. This type of cell death is different from the process of cell death by decay. Apoptosis can be brought about by some drugs used to treat cancer.                                  
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benign tumor
An abnormal growth that is not cancer and does not spread to other areas of the body.                                                                                 
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Cancer is not just one disease but rather a group of diseases. All forms of cancer cause cells in the body to change and grow out of control. Most types of cancer cells form a lump or mass called a tumor. The tumor can invade and destroy healthy tissue. Cells from the tumor can break away and travel to other parts of the body. There they can continue to grow. This spreading process is called metastasis. When cancer spreads, it is still named after the part of the body where it started. For example, if breast cancer spreads to the lungs, it is still breast cancer, not lung cancer.
Some cancers, such as blood cancers, do not form a tumor. Not all tumors are cancer. A tumor that is not cancer is called benign. Benign tumors do not grow and spread the way cancer does. They are usually not a threat to life. Another word for cancerous is malignant.                                                                              

cancer cell  

A cell that divides and reproduces abnormally and has the potential to spread throughout the body, crowding out normal cells and tissue.            


The basic unit of which all living things are made. Cells replace themselves by splitting and forming new cells (mitosis). The processes that control the formation of new cells and the death of old cells are disrupted in cancer.

Treatment with drugs to destroy cancer cells. Chemotherapy is often used with surgery or radiation to treat cancer when the cancer has spread, when it has come back (recurred), or when there is a strong chance that it could recur.                                                                                      

chor-i·on-ic adj.      The outer membrane enclosing the embryo in reptiles, birds, and mammals. In placental mammals it contributes to the development of the placenta.  
go·nad·o·tro·pin n.     A hormone that stimulates the growth and activity of the gonads, especially any of several pituitary hormones that stimulate the function of the ovaries and testes.                                            

The branch of science that deals with the structure and function of cells. Also refers to tests to diagnose cancer and other diseases by examination of cells under the microscope.                                                                

cytoxic ribonuclease
cy-tox-ic:       toxic to cells; cell-killing     
ri·bo·nu·cle·ase n:      Any of various enzymes that break down RNA. Also called RNase.                                                                           
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Finding disease. Early detection means that the disease is found at an early stage, before it has grown large or spread to other sites. Note: many forms of cancer can reach an advanced stage without causing symptoms. Mammography can help to find breast cancer early, and the PSA blood test is useful in finding prostate cancer.                                          


Identifying a disease by its signs or symptoms, and by using imaging procedures and laboratory findings. The earlier a diagnosis of cancer is made, the better the chance for long-term survival.                               
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Cancer of the blood or blood-forming organs. People with leukemia often have a noticeable increase in white blood cells (leukocytes).                 
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malignant tumor  
A mass of cancer cells that may invade surrounding tissues or spread (metastasize) to distant areas of the body.                                   

medical oncologist  

A doctor who is specially trained to diagnose and treat cancer with chemotherapy and other drugs.                                                

mes·o·the·li·o·ma n
A usually malignant tumor of mesothelial tissue, especially that of the pleura or peritoneum.                                                                            
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oncology  on-col-o-gy 
The branch of medicine concerned with the diagnosis and treatment of cancer.                                                                                       
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  phos-pho·ryl·a-tion n.
To add a phosphate group to (an organic molecule).                      

Changes in cells that may, but do not always, become cancer. Also called precancerous.                                                                            


A large molecule made up of a chain of smaller units called amino acids. Proteins serve many vital functions within and outside of the cell.   
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     ret·i·no·blas·to·ma n.A hereditary malignant tumor of the retina, transmitted as a dominant trait and occurring chiefly among infants.
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  tel·o·mere n.
Either end of a chromosome; a terminal chromosome.                   


An abnormal lump or mass of tissue. Tumors can be benign (not cancerous) or malignant (cancerous).                                                            
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The modified virus of a disease used to bring about resistance to that disease for a period of time, or even permanently. Development of a cancer vaccine is a subject of intense research.
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