Clinical application of a new monoclonal antibody (19B7) against PIVKA-II in the diagnosis of hepatocellular carcinoma and pancreatobiliary malignancies

Objectives: A new monoclonal antibody (19B7) against prothrombin induced by vitamin K absence or antagonist-II (PIVKA-II) was clinically applied in patients diagnosed with hepatocellular carcinoma and pancreatobiliary malignancies, and the results were compared with those obtained using the conventional monoclonal antibody (MU-3) against PIVKA-II. Methods: The assays were the standard E-1023 using MU-3, a high sensitivity kit using MU-3 and a highly sensitive avidinbiotin complex method, and a new monoclonal antibody (19B7) kit. Results: The rate of PIVKA-II positivity in patients with hepatocellular carcinoma (n = 182) was 44% with E-1023, 55.5% with the high sensitivity kit, and 58.2% with the new monoclonal antibody kit. Small liver cancers 1.0 in 89 of the 113 (78.8%) patients with hepatocellular carcinoma with the new monoclonal antibody kit assay level above 0.002 arbitrary units/ml, compared with <1.0 in almost all patients with pancreatobiliary malignancies. Conclusions: MU-3 has much greater affinity for PIVKA-II in hepatocellular carcinoma than does l9B7, whereas l9B7 has much greater affinity for PIVKA-II in pancreatobiliary malignancies than does MU-3. The new monoclonal antibody, 19B7, is useful for diagnosing hepatocellular carcinoma and can also distinguish patients with hepatocellular carcinoma from those with other pancreatobiliary malignancies when combined with a PIVKA-II assay using the conventional monoclonal antibody, MU-3.