Because DNA damage-induced checkpoint activation is partially regulated by ataxia telangiectasia-and-rad3-related (ATR) and ataxia-telangiectasia mutated (ATM) pathways31, we also examined the involvement of DNA damage signalings such as ATR and ATM pathways in the induction of mRNA expression of CXCL9/10/11 by T-DXd in HER2-positive GC cells. This evidence concerns the gene CXCL9 and gastric cancer.