Genetic Polymorphisms of Hepatic ABC-Transporter in Patients with Hepatocellular Carcinoma

We examined whether genetic polymorphisms of efflux transporters in hepatocytes are associated with susceptibility to develop hepatocellular carcinoma (HCC). Genetic polymorphisms of drug transporters expressed in hepatocytes were analyzed using DNA samples from hepatitis C virus (HCV)-seropositive cirrhotic patients with HCC (n = 58), and allele and haplotype frequencies were compared with those in healthy subjects (n = 61). To search for single nucleotide polymorphisms (SNPs) in HCC susceptibility genes, 34 SNPs in 6 efflux transporters [MDR1 (ABCB1), ABCC1, ABCC2, ABCC3, ABCG2 and ABCB11] were determined. No significant association was observed for any single SNP; however, some haplotypes in ABCC1 and ABCB11 were associated with HCC. Furthermore, three combinations of SNPs (3435C > T in ABCB1 and 825T > C in ABCC1), (3435C > T in ABCB1 and -15281_-15278CTCT > delete in ABCB11), and (825T > C in ABCC1 and -15281_-15278CTCT > delete in ABCB11) were significantly associated with HCC. The present study suggests that genetic variations of ABC transporters such as ABCB1, ABCB11, and ABCC1 are associated with susceptibility to develop HCC, implying that aberrant hepatic clearance of toxic substances may increase the risk of hepatocarcinogenesis. Further studies of how these polymorphisms are associated with phenotypic differences are warranted.