Table S2. Univariate analysis for OS.

Parameters	HR	95% CI	P
OS, overall survival; CLDN18.2, claudin 18 isoform 2; pos, positive; neg, negative; EGJ, gastroesophageal junction; PD-L1, programmed death-ligand 1; CPS, combined positive score; HER2, human epidermal growth factor receptor 2; EBV, Epstein-Barr virus; pMMR, mismatch repair-proficient; dMMR, mismatch repair-deficient; TMB, tumor mutational burden; HR, hazard ratio; 95% CI, 95% confidence interval.
CLDN18.2 cut-off value ≥2+, 40%
Age ≥60 vs. <60 (year)	0.951	0.764−1.183	0.650
Male vs. Female	0.797	0.628−1.012	0.062
CLDN18.2-pos vs. -neg	1.405	1.125−1.755	0.002
Non-EGJ vs. EGJ	1.080	0.587−1.400	0.561
Intestinal vs. Diffuse	0.648	0.496−0.847	0.001
PD-L1 CPS≥1 vs. <1	0.901	0.695−1.169	0.433
HER2-pos vs. -neg	0.630	0.443−0.896	0.010
EBV-pos vs. -neg	0.718	0.267−1.931	0.512
pMMR vs. dMMR	1.307	0.487−3.510	0.595
TMB≥10 vs. <10	1.352	0.766−2.386	0.298
CLDN18.2 cut-off value ≥2+, 70%
Age ≥60 vs. <60 (year)	0.951	0.764−1.183	0.650
Male vs. Female	0.797	0.628−1.012	0.062
CLDN18.2-pos vs. -neg	1.314	1.062−1.627	0.012
Non-EGJ vs. EGJ	1.080	0.587−1.400	0.561
Intestinal vs. Diffuse	0.648	0.496−0.847	0.001
PD-L1 CPS≥1 vs. <1	0.901	0.695−1.169	0.433
HER2-pos vs. -neg	0.630	0.443−0.896	0.010
EBV-pos vs. -neg	0.718	0.267−1.931	0.512
pMMR vs. dMMR	1.307	0.487−3.510	0.595
TMB≥10 vs. <10	1.352	0.766−2.386	0.298