Clinical evaluation of plasma abnormal prothrombin (PIVKA-II) in patients with hepatocellular carcinoma.

The clinical usefulness of plasma abnormal prothrombin, defined as a protein induced by vitamin K absence or antagonist-II: PIVKA-II, as a tumor marker for hepatocellular carcinoma (HCC), was evaluated. Plasma PIVKA-II concentration was determined by an enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody specific for PIVKA-II. Forty-one (65%) out of 63 patients with HCC had an abnormal PIVKA-II level above 0.13 arbitrary units (AU)/ml; the level was above 0.3 AU/ml in 33 patients (52%) and above 0.5 AU/ml in 27 patients (43%). On the other hand, most of the 282 patients with various liver diseases other than HCC had normal or slightly elevated levels of PIVKA-II. Their values were all below 0.5 AU/ml, with the exception of 2 patients with decompensated liver cirrhosis. The patients with PIVKA-II values above 0.5 AU/ml were strongly suspected of having HCC. Plasma PIVKA-II levels were not related to serum alpha-fetoprotein (AFP) levels, but were above 0.5 AU/ml in 14 (44%) out of the 32 patients whose serum AFP levels were below 400 ng/ml. In some patients with HCC, PIVKA-II was increased throughout the course of the disease, and in others it normalized after surgical resection of the tumor. We conclude that the plasma PIVKA-II assay by the ELISA method using a monoclonal antibody is a useful diagnostic tool for monitoring HCC, particularly in HCC patients with low AFP levels.