The impact of the four recently-found SNPs on liver fibrosis in chronic HBV and HCV hepatitis

Background: Recently, the influence of the four SNPs of MICA, DEPDC5, PNPLA3 and IL28B on liver disease progression or carcinogenesis was reported. However, it remains elusive whether these SNPs modify liver fibrosis in chronic viral hepatitis.
Method: Genotyping was performed for the four SNPs in 562 cases with chronic viral liver disease (N=264 in HBV and N=298 in HCV).
Result: In HCV, though the significant association with HCC occurrence was observed in MICA (P=0.02, OR 1.9) and in DEPDC5 (P=0.01, OR 2.8, in >65 year-old cases), no evident correlation with fibrosis was observed in these two SNPs. In PNPLA3, significant association with fibrosis was observed (P= 0.03, OR 2.0), but not with HCC. On the other hand no evident association with fibrosis or HCC was observed in IL28B. In HBV, there was no evident association of these four SNPs with liver fibrosis and HCC occurrence. However, significant association with G-GTP and LDL was observed in PNPLA3.
Conclusions: In HCV, PNPLA3 was an independent factor determining liver fibrosis while it was not associated with HCC occurrence directly. In HBV, roles of the four SNPs in liver fibrosis were not evident. Collectively, it was considered that liver fibrosis and hepatocarcinogenesis occur in different mechanisms between HBV and HCV chronic liver diseases.