What is Cancer?
Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body.
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Normal vs Cancerous CellsCancer cells differ from normal cells in many ways. For instance, cancer cells:
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How Does Cancer Develop?
Cancer is a genetic disease—that is, it is caused by changes to genes that control the way our cells function, especially how they grow and divide.
Genetic changes that cause cancer can happen because:
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Types of Genes that Cause Cancer
The genetic changes that contribute to cancer tend to affect three main types of genes—proto-oncogenes, tumor suppressor genes, and DNA repair genes. These changes are sometimes called “drivers” of cancer.
Proto-oncogenes are involved in normal cell growth and division. However, when these genes are altered in certain ways or are more active than normal, they may become cancer-causing genes (or oncogenes), allowing cells to grow and survive when they should not. Tumor suppressor genes are also involved in controlling cell growth and division. Cells with certain alterations in tumor suppressor genes may divide in an uncontrolled manner. |