Association Between Insertion/deletion Polymorphisms In The 3’UTR Of STN1 With Hepatocellular Carcinoma Susceptibility In A Chinese Population

Objective: To investigate whether the Indel polymorphism in the 3’UTR of STN1 is associated with hepatocellular carcinoma(HCC) susceptibility in a Chinese population and investigate the possible functional significance of the polymorphism using genotypephenotype correlation as well as bioinformatics analysis.Methods:(1) Bioinformatic tools were used to screen polymorphisms in the 3’UTR of STN1, from which we chose an Indel polymorphism that has potential function and MAF>0.05 as candidate.(2) A case-control study consisting 745 HCC cases and 945 healthy controls was performed using PCR-PAGE method. Logistic regression model was used to evaluate the association between polymorphisms and HCC susceptibility.(3) Real-time PCR was used to investigate the genotype-phenotype correlation between different genotypes of the polymorphism and the expression of STN1 in corresponding HCC tissue samples and tumor adjacent tissue samples.(4) Bioinformatic method was used to predict the effect of rs147944736 polymorphism on the conformational space of STN1.Results:(1) Genotyping results showed that rs147944736 in the 3’UTR of STN1 had good genotypic frequency distribution. The genotypic frequencies of STN1 were 0.463(Del/Del), 0.416(Ins/Del), 0.121(Ins/Ins) in case group, and 0.392(Del/Del), 0.460(Ins/Del), 0.148(Ins/Ins) in control group, respectively. There were no deviations from Hardy–Weinberg equilibrium for the controls.(2) Logistic regression analysis showed that after adjustment for sex, age, smoking status, drinking status, HBV infection and so on, the Ins/Del and Ins/Ins genotype was associated with a decreased risk of HCC compared with the Del/Del genotype of rs147944736(OR=0.76, 95% CI: 0.62-0.94; OR = 0.55, 95% CI: 0.41-0.74).(3) Results of real-time PCR demonstrated that the expression level of STN1 in HCC tissues was 2.50-fold of that in adjacent tumor tissues. Different genotypes of rs147944736 were significantly correlated with STN1 expression of different HCC tumor tissue and non-tumor tissues with different genotypes. The STN1 expression of subjects carrying ins/del and ins/ins genotype was 2.80 and 4.20 fold of that subjects carrying del/del genotype, respectively.(4) Bioinformatic method was used to predict whether the rs147944736 polymorphism has effect on the conformational space of STN1.Conclusion:(1) Our genetic association study have successfully identified that the rs147944736 polymorphism is a risk-conferring polymorphism for HCC in a Chinese population.(2) There is a genotype-phenotype correlations between different genotypes of rs147944736 and the expression of STN1 of corresponding genotypes in both HCC tumor tissue and non-tumor tissues.(3) rs147944736 polymorphism may be involved in the occurrence of HCC through changing the synthesis of telomeres by affecting the spatial conformation of STN1.