The IGF-1R targeting of miR-515-5p was disrupted by A to G nucleotides substitution in the miR-515-5p binding sites of IGF-1R 3′UTR, suggesting that the IGF-1R level in BC can be regulated by miR-515-5p binding on the polymorphic site in IGF-1R 3′UTR. The gene discussed is IGF1R; the disease is breast cancer.