N6-methyladenosine reader YTHDC2 and eraser FTO may determine hepatocellular carcinoma prognoses after transarterial chemoembolization

Abstract

Transarterial chemoembolization (TACE) has significantly improved overall survival (OS) of unresectable hepatocellular carcinoma (HCC) patients. Unfortunately, a portion of patients show no therapeutic responses to TACE. N6-methyladenosine (m6A) as well as its epigenetic writers, erasers, and readers play a crucial role in HCC development. However, it is still largely unclear how functional small nucleotide polymorphisms (SNPs) in m6A-regulating genes contribute to prognosis of TACE-treated HCC patients. In this study, potential functional SNPs were systematically evaluated to identify their roles in the prognosis of HCC patients after TACE in aChinese Han population. Employing multiple databases, we successfully annotated 55 candidate SNPs. After genotyping these SNPs in our TACE cohort, we identified three genetic variants in YTHDC2 (rs6594732, rs10071816, and rs2303718) and one SNP in FTO (rs7202116) having statistically significant associations with the OS of HCC patients treated with TACE. For example, multivariate Cox proportional hazards model indicated that the rs7202116 GG genotype carriers had markedly shorter OS and an 87% increased death risk compared with the AA carriers after TACE therapy (P = 0.002). When investigating functional relevance of these SNPs, we observed an allelic regulation of rs7202116 on FTO expression in HCC tissue samples, with higher tumor suppressor FTO expression among theA allele carriers. Our findings reported the first evidence supporting the prognostic value of m6A reader YTHDC2 and m6A eraser FTO SNPs in TACE-treated HCC patients. Importantly, our data implicated that m6A-regulating genes may be targets to improve therapeutic strategy for unresectable HCC patients.