1.What is tumor? Tumor is a kind of tissue cells in human body that proliferate abnormally without control and cause damage to the organism. 2.The difference between benign and malignant tumors (commonly known as cancer) Benign tumors can only grow locally, while malignant tumors can infiltrate locally and metastasize outward. 3.Classification of malignant tumor Cancer: common type of tumor, often occurs in lung, stomach, esophagus, breast, colon, etc.; Sarcoma: often occurs in bone, cartilage, fat, connective tissue and muscle; Lymphoma: tumor of lymph node and immune tissue origin in body; Leukemia: immature blood cells grow in large numbers in bone marrow, often causing an increase of such cells in peripheral blood. 4.Infiltration and metastasis of malignant tumor Infiltration refers to the direct migration and penetration of cancer cells into adjacent tissues, while metastasis refers to the penetration of cancer cells into lymphatic vessels and blood vessels to other parts and invade normal tissues with blood circulation. 5.Why malignant tumor can threaten people’s health and life? Cancer cells can metastasize to other parts of the body. For example, if they keep growing in brain, liver, lung, etc., they will surely destroy the structure and function of these important organs and endanger life in serious cases. Therefore, cancer should be detected early. 6.Early malignant tumor may not have any symptom Malignant tumor may not have any symptom in early stage, but as the disease progresses, it may cause symptoms such as pain, irregular bleeding, coughing and wasting. 7.Biopsy Biopsy is a method of surgical excision or endoscopy to take a small amount of diseased tissue and then observe it under microscope, and accurately determine whether there is a tumor and whether it is benign or malignant. It is the final definitive diagnosis of cancer. 5.Staging of malignant tumor (early or late disease) is based on the following three aspects: (1) the size of tumor and the depth/degree of invasion of surrounding tissues; (2) whether it invades regional lymph nodes; (3) whether it metastasizes to other parts of the body. 6. Common treatment modes of malignant tumors Surgery: Remove the tumor as much as possible. Chemotherapy: ①Adjuvant chemotherapy: postoperative chemotherapy. (2) Neoadjuvant chemotherapy: preoperative chemotherapy. For patients with large local tumors or regional metastases, they can be treated with internal chemotherapy first to get the chance of surgery. Radiotherapy: using radiation to kill tumor cells. It can be used in combination with chemotherapy. Biological therapy: I-2, IFN-α, etc. Gene therapy: such as monoclonal antibodies developed for HER-2 gene overexpression in breast cancer. Molecular targeted therapy: a novel treatment method. Interventional therapy. Traditional Chinese medicine.