Therefore, CCND1 is highly likely to be the gene that mediates rs614367 breast cancer susceptibility: variants in the enhancer region (either rs614367 or other functional variants) may be hypothesized to drive risk by disrupting E2F1/GATA3/MYC/TCF7L2/ZNF217 binding and affecting CCND1 expression. This evidence concerns the gene TCF7L2 and breast cancer.