Blood tests for cancer mostly refer to the detection of tumor markers in the blood, and generally check for common tumors, such as lung cancer, tumors of the gastrointestinal tract, stomach cancer, esophageal cancer, colorectal cancer, etc. Women mainly check breast cancer and ovarian cancer; men include prostate cancer. The cost of having a ten-item tumor marker test is about$800. If the tumor markers are significantly elevated, it may suggest having malignant tumor. If the prostate cancer antigen is significantly elevated, you may have prostate cancer. If CA125 is significantly elevated in female patients, they may have ovarian cancer. Tumor markers are more sensitive for patients with intermediate and advanced stages, but not so sensitive for early stage patients, the sensitivity is about 30%. In addition to tumor marker test, corresponding tests should be done, such as low-dose chest CT to screen for lung cancer; fecal occult blood to check whether there are tumors in the gastrointestinal tract; ultrasound can also be done to rule out breast cancer and ovarian cancer and other diseases.