In our work, median HER2 CN accessed using NGS was 15.34 (ranged from 2.67 to 116.27) in HER2-positive resectable GA patients with a majority of them (94.4%) having a HER2 CN less than 50, which was in an agreement with previous studies that median HER2 CN accessed by FISH is 11.9 (ranged from 3.30 to 43.80) and it accessed by droplet digital polymerase chain reaction is about 14 (ranged from 3 to 50) in HER2-positive GC patients (Gomez-Martin et al. 2013; Kim et al. 2020). The gene discussed is ERBB2; the disease is gastric cancer.