In a retrospective observational study that analyzed the age variation among HER2 IHC-positive patients in 27,787 biopsy specimens of gastric cancer, the rates were 7.1%, 8.1%, 9.0%, 10.9%, 11.8%, 12.6%, and 12.1% for patients aged ≤30, 31–40, 41–50, 51–60, 61–70, 71–80, and >80 years, respectively (p < 0.001) [30]. This evidence concerns the gene ERBB2 and gastric cancer.