Cancer, also known as malignancy, is a disease caused by an imbalance in cell growth and proliferation mechanisms. Malignant tumors are a type of neoplasm. Malignant tumors are named in various ways, the most common being based on the source of tumor histogenesis. Malignant tumors are also known as carcinomas, sarcomas, and maternal cell tumors. Carcinoma mainly refers to malignant tumors that originate from epithelial tissues and accounts for about 90% of malignant tumors. The most common cancers include lung cancer, liver cancer, stomach cancer, breast cancer, etc. Sarcoma mainly refers to malignant tumors originating from mesenchymal tissues. The most common sarcomas include fibrosarcoma, osteosarcoma, and rhabdomyosarcoma. Maternal cell carcinoma mainly refers to malignant tumors originating from infantile tissues. Maternal cell carcinomas include neuroblastoma and nephroblastoma. What are the malignant tumors included? What people often call cancer is actually malignant tumor. There are more than one hundred kinds of malignant tumors, mainly including esophageal cancer, stomach cancer, colorectal cancer, liver cancer, nasopharyngeal cancer, brain tumor, lung cancer, breast cancer, cervical cancer, blood cancer, bone cancer, etc. Patients with liver cancer, lung cancer, stomach cancer and breast cancer are the most common. Liver cancer, i.e. liver malignant tumor, is a common and frequent disease among surgical diseases. Liver malignant tumors can be divided into two categories: primary and secondary. Lung cancer is one of the malignant tumors with the fastest growing incidence and mortality rate and the greatest threat to the health and life of the population. Stomach cancer ranks first among all kinds of malignant tumors in China, and there are obvious geographical differences in the incidence of stomach cancer, which is significantly higher in the northwest and east coast of China than in the south. Breast cancer is a malignant tumor that occurs in the epithelial tissue of the breast gland. Ninety-nine percent of breast cancers occur in women. In addition to “cancer”, there is also a major category of malignant killers called “sarcoma”. In pathological diagnosis, malignant tumors of epithelial origin are named “carcinoma”, while malignant tumors of mesenchymal origin are called “sarcoma”. Carcinoma is more common in the elderly, while sarcoma is more common in adolescents. Specifically, epithelial tissues include overlying epithelium and glandular epithelium, which have protective, absorptive, secretory and excretory functions. Among them, covered epithelium refers to those cells covering the surface of the body and lining the luminal surface of luminal organs, such as the epithelium of skin, digestive ducts, respiratory system and urinary system, etc.; glandular epithelium mainly performs the function of secretion, such as liver, pancreas, thyroid gland and adrenal gland, etc. In “cancer”, according to the type of epithelium, it is divided into squamous cell carcinoma, adenocarcinoma, metastatic cell carcinoma and basal cell carcinoma. For example, esophageal cancer is mostly squamous cell carcinoma; gastric cancer is mostly adenocarcinoma; bladder cancer is mostly metastatic cell carcinoma, etc. Mesenchymal tissues include fiber, fat, smooth muscle, rhabdomyolus, cartilage, bone, blood vessels, lymphatic vessels and lymphopoietic tissues, etc. Therefore, sarcoma can be classified as fibrosarcoma, liposarcoma, osteosarcoma, lymphosarcoma and so on. In addition, malignant tumors that originate from embryonic tissues are called “maternal cell tumors”, such as nephroblastoma, neuroblastoma and retinoblastoma. There are also some malignant tumors with traditional names, such as leukemia, Hodgkin’s disease, melanoma and so on. It can be seen that although many diseases do not have the word “cancer” in their diagnostic names, they may still be malignant tumors and need special treatment as early as possible.