HCG does not change in lung cancer patients. Tumor markers associated with lung cancer include CEA, NSE, CYFRA21-1, etc. Elevated levels of HCG are seen in patients with pregnancy, trophoblastic diseases of the reproductive system and testicular cancer in men. HCG, known as human chorionic gonadotropin, is a hormone secreted by the trophoblast cells of the female placenta. Elevated levels of HCG can be seen in pregnant women and in certain reproductive endocrine disorders, such as hyperemesis gravidarum, uterine chorionic villus cancer, and male testicular cancer, etc. Clinically, it is used to diagnose early pregnancies, to rule out ectopic pregnancies, and to diagnose miscarriages, etc. It can also be used as a marker for malignant diseases of reproductive origin. It can also be used as a monitoring index for malignant tumors of trophoblastic origin. Patients with lung cancer usually do not show HCG changes. Elevated carcinoembryonic antigen (CEA) can be seen in some patients with lung cancer, but the sensitivity and specificity are not high. Cytokeratin 19 fragment (CYFRA21-1) is the tumor marker of choice for the diagnosis of non-small cell lung cancer, with a positivity rate of about 40% to 64%, and it can also be differentiated from small cell lung cancer.NSE (neuron-specific enolase) is a more sensitive marker for small cell lung cancer, with a sensitivity of about 80%. Patients who are suspected of having lung cancer are recommended to go to the hospital as soon as possible and consult a professional doctor to determine the next step of the examination plan, so that the diagnosis can be clarified in a timely manner and appropriate treatment can be provided.