The Association Of Genetic Polymorphisms And Tissue Expression In Long Noncoding RNA With Colorectal Cancer

Background and ObjectivesThe development and progression of colorectal cancer(CRC)which is one of the most common gastrointestinal malignant cancers is a multi-factor,multi-step and multi-phase complex process.Genetic variation might be an important factor to cancer susceptibility,in which genetic polymorphisms in long non-coding RNA(lncRNA)might be one of components.In our previous study,MALAT1 rsl 194338,RP11-650L2.2 rs149941240,RP11-108K3.2 rs2470151,RP11-392P7.6 rs10845671 and RP11-3N2.1 rs13230517 have been found to be associated with the risk of CRC.Thus the current study aimed to investigate the associations of IncRNA genetic polymorphisms and their expression with the progression of CRC.Materials and MethodsA total number of 193 CRC cases from Hangzhou First People's Hospital(from May 2013 to December 2013,95 cases)and Shaoxing People's Hospital(from January 2015 to June 2015,98 cases)were recruited as subjects.The baseline data were collected by checking the Patients' Information System.The tumor tissues and paired adjacent normal tissues were obtained during curative surgery simultaneously.The regular follow-ups were performed.DNA were extracted from tissue samples by magnetic beads method,and then genotyped using the MassARRAY Genotyping System for SNP.RNA were also extracted from tissue samples by Trizol reagent,and then detected by quantitative RT-PCR for the lncRNA expression level.Statistical analyses included two processes,description and inference.Hardy-Weinberg equilibrium(HWE)for five SNPs was tested by goodness-of-fit test chi-square analysis.Paired t tests were used to evaluate the lncRNA expression difference between tumor tissues and paired normal tissues.Anova analyses were for comparing the IncRNA relative expression level in different genotypes of lncRNA SNPs.Associations between genetic polymorphisms and their tissue expression in IncRNA and the risk of CRC death were estimated by calculating the adjusted hazard ratio and corresponding 95%confidence intervals with Cox proportional hazard regression model.Survival curves were made by Kaplan-Meier method and tested by log-rank.The data sorting and analyses were performed using SAS 9.4 and Graphpad Prism 5.ResultsThe study included 193 CRC cases(124 males and 69 females)with median follow-up of 31.5 months.Because of poor stock and quality of DNA specimens in 40 subjects,IncRNA SNP rs1194338,rs149941240,rs2470151,rs10845671 and rs13230517 were successfully genotyped in 153 subjects.Five SNPs were all in accordance with HWE.It is demonstrated in survival analyses that there was no statistically significant association between different genotypes of five IncRNA SNPs and the risk of CRC death(P>0.05).For the expression analysis of IncRNA in tissues,there were no expression results of RP11-108K3.2,RP11-392P7.6 and RP11-3N2.1 due to no specific quantitative RT-PCR primers and accordingly the expression level of MALAT1 and RP11-650L12.2 were tested.As for the expression(ACT)difference between tumor tissues and paired normal tissues,the expression level of MALAT1 and RP11-650L2.2 in tumor tissues were significantly lower than that of paired normal tissues(P<0.05).According to the relative expression level(-??CT)in CRC tissues,there was statistically difference of MALAT1 relative expression among rs1194338 genotypes(P<0.05),in which MALATI relative expression level of AA genotype was higher than that of CC genotype(P<0.05),while RP11-650L12.2 relative expression among different genotypes of rs149941240 didn't have statistically significant difference(P>0.05).Survival analyses revealed that the expression levels of MALAT1 and RP11-650L2.2 in tumor tissues were not statistically associated with the risk of CRC death(P>0.05).ConclusionsThe genotypes of MALAT1 rs1194338,RP11-650L2.2 rs149941240,RP11-108K3.2 rs247015,RP11-392P7.6 rs10845671 and RP11-3N2.1 rs13230517 were not associated with the progression of CRC.The expression of MALAT1 and RP11-650L2.2 were remarkably downregulated in CRC tumor tissues.Significant difference of MALAT1 expression were observed among different genotypes of MALAT1 rs1 194338 in CRC tissues,while there was no significant difference of RP11-650L12.2 expression among different genotypes of rs149941240 in CRC tissues.The expression levels of MALAT1 and RP11-650L2.2 in tumor tissues were not associated with the progression of CRC.