ERBB2 and gastric cancer: Previous studies have reported frequent overexpression of HER2 and PD-L1 in GAED and HAC.11,13,43–45) Trastuzumab, an anti-HER2 drug, has been shown to be effective in patients with advanced HER2-positive GC, as demonstrated in the large-scale phase 3 international ToGA clinical trial.10) Fujimoto et al. reported HER2 positivity rates of 31% in HAC and 42% in GAED,12) both higher than the 22.1% observed in conventional GC.10) These findings suggest that patients with GAED and HAC may be strong candidates for anti-HER2 therapy.