A study on sequence variations in pre‐S/surface,X and enhancer II/core promoter/precore regions of occult hepatitis B virus in non‐B,non‐C hepatocellular carcinoma patients in Taiwan

This study was to investigate the clinical significance and virologic factors of occult hepatitis B virus (HBV) infection in hepatocellular carcinoma (HCC) patients without hepatitis B surface antigen (HBsAg) or anti‐hepatitis C virus (non‐B, non‐C) in Taiwan. Serum HBV DNA (occult HBV) was detected in 90 of 222 non‐B, non‐C HCC patients and 24 of 300 non‐B, non‐C controls without HCC. Of 90 occult HBV‐infected HCC patients, the sequences of HBV pre‐S/surface, X and enhancer II/core promoter/precore genes were analyzed from 40 patients. Direct sequencing of such genes was also performed in 24 non‐B, non‐C controls without HCC and 40 HBsAg‐positive HCC controls. Compared with non‐B, non‐C controls without HCC, non‐B, non‐C subjects with HCC had significantly higher prevalence of occult HBV (p < 0.0001). Moreover, M1I and Q2K in pre‐S2 gene and G1721A were more common in occult HBV‐infected patients with HCC than in those without HCC. Compared with the HBsAg‐positive HCC controls, occult HBV‐infected HCC patients had higher frequencies of M1I and Q2K in pre‐S2 gene, G185R and S210N in surface gene, A36T and A44L in X gene, and G1721A in enhancer II gene, and had lower rates of pre‐S deletions and A1762T/G1764A, A1846T, G1896A and G1899A in core promoter/precore genes. Multivariate analysis showed Q2K in pre‐S2 gene, G1721A and A1846T were independent factors for occult HBV‐infected HCC. Our study suggested that the virological factors of HBV related to HCC were different between occult HBV‐infected and HBsAg‐positive patients. The G1721A, M1I and Q2K in pre‐S2 gene may be useful viral markers for HCC in occult HBV carriers. © 2009 UICC