In vitro data suggest synergy between oxaliplatin and 5-FU. The combination of oxaliplatin with 5-fluorouracil produced objective response rates ranging from 27-34% in two studies of patients with prior chemotherapy. Capecitabine was designed as an orally administered, tumor selective fluoropyrimidine, preferentially converted to 5-FU at the tumor site by the higher levels of pyrimidine nucleoside phosphorylase (PyNPase) in tumor tissues compared to normal tissues. The end result is higher concentrations of 5-fluorouracil in tumor relative to surrounding normal tissue. Trastuzumab is synergistic in vitro with multiple chemotherapeutic agents including the platinum compounds. Studies have shown the efficacy of trastuzumab combined with chemotherapy in patients with HER2 overexpressing metastatic breast cancer. This trial will investigate the activity of capecitabine and oxaliplatin administered with trastuzumab (CAPOX-T) in patients with HER2 overexpressing in patients with advanced disease.