ERBB2 and gastric cancer: For example, HER2 oncogene amplification and HER2 protein overexpression occur in approximately 17–20% of gastric cancer patients, and it is more common in intestinal gastric cancer and cancers in the proximal stomach or gastroesophageal junction [21], according to HER2 gene Positive expression, the use of trastuzumab prolonged the survival rate of patients [22,23].