Overall, these data strongly encourage further investigation on the potential use of a double pathway inhibition strategy in the subgroup of “double positive” breast cancer patients (RANK-positive and EGFR- and/or ErbB2-positive) through the existing molecules targeting RANKL/RANK pathway and ErbB family members (e.g. denosumab plus anti-EGFR drugs, such as erlotinib or panitumumab; or denosumab plus anti-ErbB2 drugs, such as lapatinib or trastuzumab). This evidence concerns the gene ERBB2 and breast cancer.