The diagnostic value of hepatitis B core-related antigen in occult hepatitis B virus infection and its related hepatocellular carcinoma.

[OBJECTIVES] Occult hepatitis B virus (HBV) infection (OBI) has come to the fore recently. The study aimed to evaluate the value of serum hepatitis B core-related antigen (HBcrAg) in diagnosing OBI in hepatitis B surface antigen (HBsAg)-negative population, and the risk of OBI-related hepatocellular carcinoma (HCC) tumorigenesis, metastasis, and recurrence after radical surgery.

[DESIGN AND METHODS] The OBI status was determined by nested polymerase chain reaction. HBcrAg and common HBV clinical indicators were compared between the OBI and non-OBI groups. A detection pathway based on HBcrAg was established for OBI diagnosis. HBsAg-negative patients (124 HCC and 53 non-HCC) were enrolled for risk assessment of HBcrAg in OBI-related HCC.

[RESULTS] A detection pathway for diagnosing OBI based on HBcrAg combined with hypersensitive HBV DNA and pregenomic RNA was established with a 78.9% sensitivity and a 100% specificity. Multivariate logistic regression showed that serum HBcrAg-positive was associated with a high risk of HCC in OBI patients (adjusted odds ratio: 3.57, P = 0.037). Kaplan-Meier survival analysis showed that the cumulative recurrence rate at 84 months in the HBcrAg-positive group was higher than HBcrAg-negative one (50.0% vs 11.8%, hazard ratio = 4.995, P = 0.016).

[CONCLUSION] HBcrAg is a promising serum marker for the diagnosis of OBI in HBsAg-negative population. HBcrAg is related to OBI-related HCC and is valuable in evaluating recurrence after radical resection surgery.