The normal value of gastrin-releasing peptide precursor should be less than 50pg/ml. gastrin-releasing peptide precursor more than 50pg/ml has the possibility of cancer. 1. Gastrin-releasing peptide precursor exists in the nervous system, gastrointestinal tract and respiratory system of mammals, it is a kind of brain and intestinal hormone with high sensitivity and specificity, and it is a tumor marker for small cell lung cancer. 2. Elevated levels of gastrin-releasing peptide precursor are seen in a variety of tumors of neuroendocrine origin, including small-cell lung cancer, medullary thyroid carcinoma, undifferentiated large-cell lung cancer with neuroendocrine function, and other neuroendocrine malignancies. Gastrin-releasing peptide precursors above 50 pg/ml have the potential for cancer. If the test result is higher than the normal range, it should be taken seriously, and it is recommended to consult the doctor in time, clarify the cause of the disease and follow the doctor’s instructions for comprehensive treatment.