Association of KRAS Gene and microRNA-124-3p in Sporadic Colorectal Tumours

Aim: To reveal the exonic and 3’UTR sequences of KRAS, TP53, APC, BRAF, PIK3CA genes in sporadic colorectal tumors and to investigate the clinical relevance of 3’UTR variations in miRNA profiles. Methods: In the study, the exonic and 3’UTR sequences of five genes in 12 sporadic colorectal tumors were extracted by next generation sequencing. In tumors with variation in the 3’UTR region, the changes caused by the variation in the miRNA binding profile were detected. The expression profile of these miRNAs in colorectal and other solid tumors compared to normal tissue was determined. Pathway analysis was performed to determine which signaling pathways miRNAs affect. Results: Case-10 in our study was wild type KRAS and received cetuximab treatment and developed drug resistance. In this case, it was concluded that the expression of KRAS increased and tumorigenesis progressed due to miRNAs that do not bind to this region due to variations in the 3’UTR region. Among these miRNAs, hsa-miR-124-3p was found to have decreased expression in colorectal tumors and to be associated with the ECM-receptor interaction pathway. Conclusion: Variations in the 3’UTR regions of genes critical in the process of carsinogenesis are associated with drug resistance and the process of tumorigenesis.