In vitro, RC48 has exerted much stronger antitumor activity compared to T-DM1, an FDA-approved ADC drug, in HER2 positive breast and gastric cancer cells, also in the trastuzumab- and lapatinib-resistant xenograft tumor models, suggesting its potential as an improved therapy for HER2-positive cancers [14]. This evidence concerns the gene ERBB2 and gastric cancer.