ERBB2 and gastric cancer: HER-2 is one of the therapeutic gastric cancer biomarker An open-label, randomized-controlled, phase III clinical trial investigated the efficacy of trastuzumab (a monoclonal antibody) against HER-2, in combination with chemotherapy for the treatment of HER-2-positive gastric cancers, and reported that trastuzumab treatment significantly improved overall survival and disease free survival times as compared to chemotherapy alone (9).