Table 1.

Studies that evaluated the prognostic role of CLDN 18.2 in GEJ/GC. OS: overall survival; * 19.8% (N = 85) gastric cancer. The color is used to highlight the statistical significance of the last for studies, as opposed to the other studies who did not present a statistical significance.

Reference	Type of Study	Country	N	Definition of CLDN 18.2 Positivity	Frequency	OS Impact
Zhu et al., 2013 [52]	Retrospective	China	329	Immunoreactivity score (IS ≥ 4)	53.2%	p = 0.469
Hong et al., 2020 [50]	Prospective	Republic of Korea	430 *	>5%	14.1%	p = 0.101
Dottermusch et al., 2019 [43]	Retrospective	Germany	481	Positive histoscore (H-score)	42.2%	p = 0.439
Baek et al., 2019 [44]	Retrospective	Republic of Korea	367	>50%	29.4%	p = 0.914
Arnold et al., 2020 [53]	Retrospective	Germany	414	Immunoreactivity score (IRS) > 8	17.1%	p = 0.944
Pellino et al., 2021 [54]	Retrospective	Italy	350	≥75%	33.4%	p = 0.926
Kayikcioglu et al., 2023 [55]	Retrospective	Turkey	65	Any positive staining	73.8%	p = 0.09
Kubota et al., 2023 [56]	Retrospective	Japan	408	≥75%	24%	p = 0.191
Resnick et al., 2005 [57]	Retrospective	USA	146	≥2+	-	p = 0.007
Jung et al., 2011 [58]	Retrospective	Republic of Korea	72	≥25%	44.4–73.6%	p = 0.046
Jun et al., 2014 [41]	Retrospective	Republic of Korea	134	≥10%	25.5–29.9%	p = 0.005
Kohmoto et al., 2020 [59]	Retrospective	Japan	394	High mRNA expression	18%	p = 0.0013