Cancer or non-trophoblastic cancer is, in the USA hCG Reference Service experience, the explanation for 9.0% of women being positive for hCG outside of pregnancy. As we now know, cancer cells produce a variant of hCG called hCG free ß-subunit or hyperglycosylated hCG free ß-subunit, at low concentrations. This variant actually drives the cancer, causing it to grow and invade. One of the biggest problems in being found to have positive hCG variants due to cancer, is it does not ell you where the cancer is hiding. It could be a brain cancer, a blood cancer, a bone cancer or a lung cancer. The patient need an MRI scan of the head and pelvis and a CT-scan of the chest, and loads of blood tests to try and find the cancer primary. Only once the primary is found and pathlogy histology tests are performed can the cancer be truly confirmed and identified.
As discussed in the USA hCG Reference Service web site, their are two other explanations for hCG free ß-subunit production, these are PSTT (Placental site trophoblastic disease) and Familial hCG Syndrome. These two possibilities must be investigated before it is concluded that a patient has cancer. One type of cancer produces high concentrations of hCG. The detection of higher concentrations of hCG (>200 mIU/ml in blood) suggests these malignancies, these are ovarian and testicular germ cell malignancies.