What is cancer?
The body is made up of many types of cells. Normally, cells grow, divide and then die. Sometimes, cells mutate (change) and begin to grow and divide more quickly than normal cells. Rather than dying, these abnormal cells clump together to form tumors. If these tumors are cancerous (also called malignant tumors), they can invade and kill your body's healthy tissues. From these tumors, cancer cells can metastasize (spread) and form new tumors in other parts of the body. By contrast, noncancerous tumors (also called benign tumors) do not spread to other parts of the body.
There are many different types of cancer, but all cancers begin with abnormal cells growing out of control. The type of cancer is determined by what type of cells begin to grow abnormally and where in the body the abnormal growth occurs. The most common cancers in adults are skin cancer, lung cancer, colon cancer, rectal cancer, breast cancer, endometrial cancer, ovarian cancer and prostate cancer.
Written by familydoctor.org editorial staff