Human Chorionic Gonadotropin
Human chorionic gonadotropin (HCG) is normally produced by the placenta during pregnancy. In fact, HCG is sometimes used as a pregnancy test because it increases early within the first trimester. It is also used to screen for choriocarcinoma (a rare cancer of the uterus) in women who are at high risk for the disease, and to monitor the treatment of trophoblastic disease (a rare cancer that develops from an abnormally fertilized egg). Elevated HCG levels may also indicate the presence of cancers of the testis, ovary, liver, stomach, pancreas, and lung. Pregnancy and marijuana use can also cause elevated HCG levelsβhCG is occasionally secreted by a group of cancers called teratomas. When a patient is suspected of harboring a teratoma (often found in the testes and ovaries but also in the brain as a dysgerminoma), a physician may consider measuring βhCG. Elevated levels cannot prove the presence of a tumor, and low levels do not rule it out. Nevertheless, elevated βhCG levels fall after succesful treatment (e.g. surgical intervention or chemotherapy), and a recurrence can often be detected by the finding of rising levels.