Tumors can occur in every part of the human body, from the extremities, face, body surface to internal organs. The most frequently occurring gastrointestinal tumors are related to diet, including esophageal cancer, stomach cancer, and colorectal cancer. Patients will have obvious choking sensation when eating, difficulty in swallowing, pain behind the sternum, epigastric pain, abdominal distension, diarrhea, and blood in the stool. As for the occurrence of lung cancer of respiratory system, patients will have coughing, coughing sputum, hemoptysis, chest pain, chest tightness, and in severe cases, they will have difficulty in breathing. As for liver tumor, the most common patient with liver cancer will have obvious pain in the right upper abdomen, loss of appetite and weight loss, and later on the development of tumor with extensive metastasis in the abdominal cavity will also be complicated by large amount of ascites.