Higher expression of MFSD2A in tumor tissues of AGC patients was associated with better response to anti-PD-1 immunotherapy...The overexpression of MFSD2A in GC cells enhanced the efficacy of anti-PD-1 immunotherapy in vivo by reprogramming the tumor microenvironment (TME)...MFSD2A potentially serves as a predictive biomarker for anti-PD-1 immunotherapy response in AGC patients.