ERBB2 and breast cancer: Since the FDA approved Herceptin® for the treatment of metastatic breast cancer (Pegram et al, 1998; Cobleigh et al, 1999; Roche and Ingle, 1999; Slamon et al, 2001), and in order to determine whose patients might benefit from this new therapy, there has been a need to evaluate precisely the HER2 status of breast cancer specimens.