1.Definition A.Nomenclature Most cancers are named for the organ or type of cell in which they begin. Carcinomas are the most common types of cancer, arise from the cells that cover external and internal body surfaces,such as Lung,breast,and colon. Sarcomas are cancers arising from cells found in the supporting tissues,such as bone,cartilage软骨， fat,connective tissue,and muscle. Leukemic▣白血病and Lymphoma淋巴瘤are cancers that arise in blood-forming cells.The abnormal cells circulate in the bloodstream and lymphatic system. They may also invade (infiltrate)body organs and form tumors.• Most cancers are named for the organ or type of cell in which they begin. • Carcinomas 癌are the most common types of cancer, arise from the cells that cover external and internal body surfaces, such as Lung, breast, and colon. Sarcomas肉瘤 are cancers arising from cells found in the supporting tissues, such as bone, cartilage软骨, fat, connective tissue, and muscle. • Leukemia白血病 and Lymphoma淋巴瘤 are cancers that arise in blood-forming cells. The abnormal cells circulate in the bloodstream and lymphatic system. They may also invade (infiltrate) body organs and form tumors. 1. Definition A. Nomenclature