Cancer is the disordered and abnormal growth of cells that, dividing rapidly, form tumors somewhere in the body and can spread to other regions, invading tissues and organs. There are more than 200 types of cancer, which are divided into: Carcinomas: tumors in epithelial tissues, such as skin or mucous membranes; Sarcomas: tumors in connective tissues, such as bone, muscle, or cartilage; Leukemias: in the tissue that produces blood (bone marrow) Lymphomas: cancer in cells of the immune system; Central Nervous System Cancer: tumor develops in tissues of the brain and spinal cord.