ROC analysis identified KRAS as a potential predictive biomarker for chemotherapy response.<h4>Conclusion</h4>Variants rs712 and rs9266 in the KRAS 3'UTR impair miRNA binding, enhancing KRAS expression and tumorigenesis, while elevated hsa-let-7c and hsa-miR-181c levels predict favourable survival outcomes in BC patients. Here, KRAS is linked to breast cancer.