What are the signs of digestive system tumors?

Digestive system tumor markers include carbohydrate antigen and carcinoembryonic antigen, as well as alpha-fetoprotein and alkaline phosphatase. Normal need to do fasting blood test to diagnose, if the value of the test is high, it does not mean that there is a tumor, but also need to make a diagnosis according to pathological sections, for gastric cancer and liver cancer and colon cancer can be clearly diagnosed.