The results showed that the CLDN18 expression of primary gastric tumor was positive in 52.9% (18/34) patients in the “effective” group and 54.2% (13/24) in the “ineffective” group (χ2 = 0.071, P = 0.503, Supplementary Fig. 9a), while the CLDN18 expression of metastatic tumor was positive in 31.58% (12/38) patients in the “effective” group and 30.43% (7/23) in the “ineffective” group (χ2 = 0.009, P = 0.925, Supplementary Fig. 9b). This evidence concerns the gene CLDN18 and gastric neoplasm.