overview cancer Cancer is a group of diseases characterized by uncontrolled, abnormal cell growth and spread throughout the body. It is a complex and multifaceted disease that affects millions of people worldwide. Despite advances in research and treatment, cancer remains one of the leading causes of death worldwide. type of cancer There are more than 100 types of cancer, each classified according to the type of cell that is first affected. The most common cancer types are: carcinoma: This type of cancer begins in the skin or tissue that lines or covers internal organs. sarcoma: This type of cancer begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. leukemia: This type of cancer begins in blood-forming tissues, such as the bone marrow, and makes abnormal blood cells that circulate in the blood. Lymphoma: This type of cancer starts in cells of the immune system and can affect the lymph nodes, spleen, and other parts of the body. cause o...