- Documented overexpression of Her2(ErbB2) of IHC 3+ or FISH positive, in primary or metastatic tumor tissue is required for enrollment into the study; by local testing or central laboratory testing determined by country of residence. NB. Approximately, 51 subjects will be enrolled in a single stage design to test for efficacy in women from China and Hong Kong. Due to the fact that trastuzumab is not commonly prescribed in China and Hong Kong, the current study allows up to 40% of subjects who are trastuzumab naïve to be enrolled.