How many types of cancer are there?

There are over 100 different kinds of cancer, according to the National Cancer Institute. Each cancer belongs to one of five categories: leukemia, carcinoma, sarcoma lymphoma and melanoma and cancers of the nervous systems.

Leukemia is cancer that begins in tissue responsible for making blood cells, according to the National Cancer Institute. The damaged tissue then produces large numbers of abnormal blood cells. Carcinoma begins on the skin or on the first layer of tissue on organs. Sarcoma is cancer that begins on connective tissue, such as bones, cartilage or blood vessels. Lymphoma and melanoma are grouped together, because they both begin in the immune system. Finally, nervous system cancers begin in the tissue of the brain and spinal cord.