ERBB2 and breast cancer: However, in women with HER2+ BC, the approval of the anti-HER2 monoclonal antibody trastuzumab in the year 2000 for the treatment of metastatic BC and in 2006 for the treatment of early BC considerably improved the prognosis of the disease - the drug becoming the standard of treatment for HER2+ BC in both the metastatic and early disease settings.