Compared with normal liver tissue and cirrhosis, the pooled ORs of GSTP1 promoter region methylation in HBV-related HCC cancer tissues were 6.05 (95% CI =1.20-30.52) and 5.21 (95% CI =2.19-12.41), respectively.
Under abnormal conditions the excessive reactive oxygen species generation results in genetic predisposition of various genes (as ADH, ALDH, CYP2E1, GSTT1, GSTP1 and GSTM1) involved in xenobiotic metabolic pathways, associated with susceptibility to different liver related diseases such as fibrosis, cirrhosis and hepatocellular carcinoma.
When we used an assay targeting the 3' region, we found that the methylation of the 5'-end of the GSTP1 promoter was significantly more specific than that of the 3'-end (97.1% vs. 60%, p<0.0001 by Fisher's exact test) for distinguishing HCC (n = 120) from hepatitis (n = 35) and cirrhosis (n = 35).
Similarly, GSTP1 promoter hypermethylation was detected for the first time in 16 of 32 (50%) of circulating tumor DNA in the peripheral serum from HCC patients and 4 of 8 (50%) cirrhosis tissues and 3 of 8 (37.5%) corresponding serum DNA from cirrhosis patients.
Cirrhosis is more likely to develop in C282Y homozygotes with the GSTP1 Val/Val genotype than in those with non-Val/Val genotypes, which in part explains the variable phenotypic expression of HHC and highlights the central role of oxidative stress in its pathogenesis.
Polymorphisms in glutathione S-transferases GSTM1, GSTT1 and GSTP1 and cytochromes P450 CYP2E1 and CYP1A1 and susceptibility to cirrhosis or pancreatitis in alcoholics.