Is pregnancy-associated plasma protein A a tumor marker?

Pregnancy-associated plasma protein A (PAPP-A) was measured in 159 patients with various nontrophoblastic tumors. In three patients with trophoblastic tumors, PAPP-A and human chorionic gonadotropin (hCG) were measured before operation and weekly thereafter. Circulating levels of PAPP-A in patients with nontrophoblastic tumors were not significantly different from the levels in the matched control groups. Circulating levels of PAPP-A and hCG were significantly elevated preoperatively in patients with trophoblastic tumors, whereas the postoperative concentrations of both proteins gradually decreased. The conclusion is that, probably, PAPP-A cannot be considered to be a marker for nontrophoblastic disease, and that measurements of PAPP-A in patients with trophoblastic cancers do not provide any advantage over measurements of hCG.