SERPINA3 and cancer: In TCGA-STAD, a six-gene signature (NOTUM, APOA2, SERPINA3, NKD1, GGH, BPIFB1) correlated with prolonged survival and favorable immune infiltration, with conserved immune-modulatory patterns across multiple cancer types.<h4>Conclusions</h4>This study identifies NOTUM, SERPINA3, and CD8<sup>+</sup> T cell density as spatially resolved, clinically actionable predictors of nICT response in LAGC.