Study And Analysis Of SNPs And Downstream Genes Related To The Prognosis Of Colon Cancer Based On Bioinformatics

Colorectal cancer(CRC)has the second fatality rate and the third most common malignant tumor among all cancers in the world.The 5-year survival rate of CRC was about 64%,but dropped sharply to 12%after metastasis.The existing limitations of CRC treatment methods and treatment targets greatly limited the prognosis and survival of CRC patients.The study of SNPs(Single Nucleotide Polymorphisms)and genes related to the prognostic risk of CRC can assist people to understand the potential pathogenic mechanism of CRC,and provide potential targets for drug therapy,aid people to improve CRC prevention strategies and reduce the risk of disease,but also aid to improve the prognosis of CRC patients.Although GWAS(Genome-Wide Association Studies)has identified many SNPs and candidate loci related to CRC risk,there is little insight into the functional annotation and potential regulatory mechanism between them.In this study,several new potential CRC key SNPs with risk-related and corresponding candidate target genes were identified by bioinformatics methods such as GWAS combined with eQTL(Expression Quantitative Trait Loci)analysis and survival analysis.The relationship between SNPs and its corresponding candidate target genes is:rs10490785 matched to ABHD5,rs4339237 matched to ART3,rs9200matched to C6,rs4660165 and rs4660603 matched to HEYL.In order to screen SNPs,with different allele-specific transcriptional activity,double luciferase reporter genes were used to verify.Double luciferase reporter gene assay showed that only rs4660165locus had allele-specific transcriptional activity differences in both CRC cell lines(HCT 116 and LoVo).After that,the analysis of the histone modification data near the rs4660165 site showed that it had the characteristics of enhancers,which provides the basic conditions for the interaction between it and the candidate target genes.Hi-C and Virtual 4C data analysis showed that there was interaction between the locus and the candidate target gene HEYL.Then the transcription factor binding study of rs4660165site found that A allele of rs4660165 can specifically bind to transcription factor REST to promote the expression level of HEYL.Immune infiltration is an important process in the development of cancer.Then we explored the role of HEYL in the process of immune infiltration of CRC.In this study,by analyzed the effect of different somatic cell copy number variation of HEYL on the tumor infiltration level of immune cells,it was found that except CD4~+T cells and macrophages,the infiltration level of other immune cells was affected by the variation of somatic cell copy number of different types of HEYL.Then,the correlation between the expression level of HEYL and different levels of immune cell infiltration in CRC was analyzed,and the results showed that there was a strong positive correlation between the infiltration level of CD4~+T cells and macrophages and the expression level of HEYL(correlation coefficient>0.5).By analyzing the relationship between different kinds of immune cells and prognostic survival of CRC,it was found that the level of immune infiltration of CD8~+T cells was significantly correlated with prognostic survival time.In summary,this study found CRC prognosis-related SNPs locus rs4660165 and its candidate target gene HEYL with different allele-specific transcriptional activity.The study on the mechanism of their interaction found that rs4660165 may regulate the expression level of HEYL through A allele specific binding to transcription factor REST,the effect of HEYL on immune infiltration of CRC found that HEYL may affect the development of CRC by participating in the regulation of immune infiltration.