ERBB2 and gastric cancer: 6 HER2 overexpression varies in different regions of the world with reported high expression in India (44%) 7 and low expression in China (6.9%). 8 In another study, Van Cutsem et al, reported similar proportions of HER2 overexpression from Europe (23.6%) and Asia (23.9%) but slightly lower from Central /South America (16.1%). 9 HER2 overexpression rates were higher in intestinal (31.8%) than diffuse (6.1%) type gastric cancer.