TNFRSF11B and breast cancer: Although the mechanisms through which OPG plays a role in the pathogenesis of breast cancer are not fully delineated, risk factors include single nucleotide polymorphisms (SNPs) in the OPG gene, effects on the TNF-related apoptosis-inducing ligand, OPG protein levels, the interplay of OPG protein levels with BRCA mutations, and the overexpression of certain receptors [14].