Serum levels of des-gamma-carboxy prothrombin measured using the revised enzyme immunoassay kit with increased sensitivity in relation to clinicopathologic features of solitary hepatocellular carcinoma

Abstract

Background: Des-gamma-carboxy prothrombin (DCP) is an established marker for hepatocellular carcinoma (HCC), but the conventional enzyme immunoassay (EIA) kit lacks adequate sensitivity. Thus, a revised EIA kit with increased sensitivity has been developed. In this kit, the sensitivity has increased while high specificity to HCC has been maintained. The authors have already reported the clinical usefulness of this revised EIA kit. In this study, they examined the serum levels of DCP measured by this revised EIA kit in relation to the clinicopathologic features of solitary HCC.

Methods: Fifty-six patients with solitary HCC who underwent hepatectomy were studied. The relation between the greatest dimension and the histologic differentiation of HCC was investigated in these 56 patients, as were the serum levels of DCP measured by the revised EIA kit (Sensitive DCP), alpha-fetoprotein (AFP), and DCP measured by the conventional EIA kit (DCP). The cutoff value for Sensitive DCP was set at 40 mAU/mL, and the values for AFP and DCP were 20 ng/mL and 100 mAU/mL (0.1 AU/mL), respectively.

Results: The positivity rates for Sensitive DCP, AFP, and DCP (n = 56) were 53.6%, 53.6%, and 35.7%, respectively, and the rate was 73.2% when Sensitive DCP was used in combination with AFP (Sensitive DCP + AFP). The positivity rates for these markers were as follows: 1) When the greatest dimension of HCC was more than 3 cm (n = 16) and less than 2 cm (n = 23), the rates were 81.3% and 30.4% for Sensitive DCP, 68. 8% and 39.1% for AFP, 56.3% and 13.0% for DCP, and 93.8% and 56.5% for Sensitive DCP + AFP. 2) When HCC was moderately to poorly differentiated (n = 41) and well differentiated (n = 15), the rates were 68.3% and 13.3% for Sensitive DCP, 61.0% and 33.3% for AFP, 48. 8% and 0% for DCP, and 85.4% and 40% for Sensitive DCP + AFP. 3) When HCC was either more than 3 cm or moderately to poorly differentiated (n = 42) and either less than 2 cm or well differentiated (n = 27), the rates were 69.0% and 29.6% for Sensitive DCP, 61.9% and 37.0% for AFP, 47.6% and 11.1% for DCP, and 85.7% and 51.9% for Sensitive DCP + AFP.

Conclusions: DCP measured by the revised EIA kit with increased sensitivity has a stronger correlation than AFP with size and histologic differentiation of HCC. This Sensitive DCP is a very useful marker for HCC and should be used in combination with AFP.