Trastuzumab and Vinorelbine in Advanced Breast Cancer

OBJECTIVES: Primary * To assess the objective response rate (ORR) of trastuzumab and vinorelbine in patients with metastatic breast cancer with HER2 negative primary tumors and HER2 positive circulating tumor cells. Secondary * To describe the number of CTCs and the CTCs characteristics before and after therapy, and to explore the correlation of these findings with response. * To further characterize the safety and tolerability. * To evaluate progression-free survival. * To evaluate clinical benefit rate \[complete response (CR)+partial response (PR)+stable disease (SD)\>24 weeks\]. Exploratory * To determine the clinical feasibility of high-throughput mutation profiling on circulating tumor cells (CTCs).