ERBB2 and gastric cancer: Patients with unresectable metastatic or recurrent gastric cancer, 20–74 years of age and human epidermal growth factor 2 (HER2)-negative status, will be assigned in a 1:1 ratio to receive either S-1 40 mg/m2 bid for 21 days plus cisplatin 60 mg/m2 (day 8) every 5-week cycle or capecitabine 1000 mg/m2 bid for 14 days plus cisplatin 80 mg/m2 (day 1) every 3-week cycle.