An in vitro study showed that the bispecific antibody MDX-447, which targets FCGR1A, mediated the efficient lysis of breast cancer cells, and the results from phase II and phase III clinical trials of MDX-447 in prostate and breast cancers have shown some efficacy (Repp et al. 1995; Curnow 1997). This evidence concerns the gene FCGR1A and breast cancer.