All the blood tests are normal, but it cannot exclude the possibility of cancer. If the patient has related suspicious symptoms, he/she can consult a professional hospital for diagnosis, and should not guess on his/her own. The blood test is mainly to check the tumor markers in the blood and determine whether there is a possibility of malignant tumors through its value. Tumor marker is a special chemical substance secreted by tumor cells, when suffering from a tumor, this substance will be released into the blood, which can be detected by blood test. Elevated tumor markers are not necessarily cancerous, but can also be seen in benign diseases, such as pregnancy, active hepatitis, gastrointestinal inflammation, etc., which require further examination for differential diagnosis. Some malignant tumors do not release this substance into the blood, so it cannot be detected by blood test, so although the tumor marker is normal, it cannot exclude the possibility of malignant tumor. Therefore, for cancer screening, in addition to blood test, imaging test and pathology biopsy are also needed to make a clear diagnosis.