Clinical usefulness of des-γ-carboxy prothrombin assay in early diagnosis of hepatocellular carcinoma

Des-γ-carboxy prothrombin (DCP) was evaluated as a serological marker for hepatocellular carcinoma (HCC), particularly in patients with early HCC. In 1192 patients with various diseases, plasma DCP levels were measured by a newly developed enzyme immunoassay method using an anti-DCP monoclonal antibody. Of the 254 patients with HCC, 143 (56%) had abnormal DCP levels of greater than 0.1 AU/ml. In contrast, elevated DCP levels were rarely observed in patients with chronic hepatitis, liver cirrhosis, metastatic liver cancer, and other malignant tumors. Because no correlation was observed between DCP and α-fetoprotein (AFP), the combined measurement of these two complementary markers appears to be useful in the diagnosis of HCC. Since normal levels were observed in 29 of 30 patients (97%) with small liver tumors measuring 2 cm or less in diameter, the diagnostic application of the DCP assay to small liver tumors is limited. However, in patients with tumors larger than 2 cm, the plasma DCP assay may even be more useful than AFP. Among 46 patients with liver cirrhosis or chronic hepatitis who subsequently developed HCC, significantly increased DCP and AFP levels were observed in nine patients (20%) and 14 patients (30%), respectively, when a tumor was detected. When the results of both assays were combined, 19 patients (41%) had elevated levels of one or both markers. Although the plasma DCP assay alone is not sensitive enough to detect early small liver cancers, it could be applied as a complementary tumor marker together with AFP. The use of both these markers together with imaging modalities in the regular follow-up of patients with chronic liver disease who are at high risk for HCC might be of great benefit.