A hormone found in the blood and urine during pregnancy. It may also be found in higher than normal amounts in patients with some types of cancer, including testicular, ovarian, liver, stomach, and lung cancers, and in other disorders. Measuring the amount of beta-hCG in the blood or urine of cancer patients may help to diagnose cancer and find out how well cancer treatment is working. Beta-hCG is a type of tumor marker. Also called beta-human chorionic gonadotropin.