Although some of these genes, such as DARPP-32 (Hamel et al., 2010) and GRB7 (Giricz et al., 2012), have already been reported to be associated with poor prognosis and survival of cancer patients, there is currently limited information available on whether any of these genes may play a role in HER2-driven breast tumor formation or treatment resistance. This evidence concerns the gene GRB7 and breast neoplasm.