Mining of single nucleotide polymorphisms in the 3' untranslated region of liver cancer-implicated miR-122 target genes

Currently there has been a lot of focus on the microRNA (miR)-122 to understand the genetics of hepatocellular carcinoma (HCC), pathology of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, hepatic insulin resistance, and lipid metabolism (1-4). Interestingly, miR-122 expression levels were significantly reduced than the normal levels in HBV-associated liver cancer, but not in HCV related liver cancer (5). Also, there is an overwhelming amount of data suggesting the role of single nucleotide polymorphisms (SNPs) in hepatic genes and its association with the altered risk/development of hepatic cancer and its progression. Polymorphisms in the miRNA-binding sites of the target genes are more frequent than SNPs in miRNA genes and therefore, it is considered that polymorphisms in the cytokines and other genes have correlations with chronic HBV or HCV infections. These SNPs in the miRNA binding sites of the target genes can potentially enhance or weaken the interaction between the miRNAs and the target transcripts. Therefore, it is important to study the SNPs in miR-122 binding sites of the target genes to understand the genetic basis of HCC.