ERBB2 and gastric cancer: In the HERBIS-1A trial (a phase II trial of S-1 + cisplatin + trastuzumab for treatment of patients with HER2-positive gastric cancer (IHC 3+ or IHC 2+ and FISH positive) that was conducted in Japan [15], 83% of subjects (45/54) had an IHC score of 3+ while 17% (9/54) had an IHC score of 2+.