To investigate the expression characteristics of Claudin 18.2 (CLDN18.2) in gastric adenocarcinoma tissues, and to compare the consistency of immunohistochemical detection results among four antibodies with different clone numbers (43-14A, OTIR157B5, MXR038, and RM510) on the Ventana BenchMark platform.

A total of 159 gastric adenocarcinoma specimens (49 surgical specimens and 110 biopsy specimens) diagnosed in the Department of Pathology, Xinzhou Hospital Affiliated to Shanxi Medical University from 2022 to 2025 were collected. CLDN18.2 expression was detected on the Ventana BenchMark platform. The positive cutoff value was defined as the proportion of moderately to strongly positive adenocarcinoma cells ≥75%. The consistency of detection results among the four antibodies on the same platform was evaluated.

The positive rates of the four CLDN18.2 antibodies in gastric adenocarcinoma were as follows: 40.2% (64/159) for 43-14A, 40.2% (64/159) for OTIR157B5, 9.4% (15/159) for MXR038, and 6.9% (11/159) for RM510, with statistically significant differences among the groups (P＜0.05). There were no statistically significant differences between clone OTIR157B5 and 43-14A in overall, surgical, and biopsy specimens (all P＞0.05), indicating good compatibility with the Ventana platform. In contrast, clones MXR038 and RM510 showed statistically significant differences compared with 43-14A across all specimen groups (all P＜0.001), indicating poor platform compatibility. Using 43-14A as the reference, the sensitivity and specificity of OTIR157B5 were 89.1% and 92.6%, respectively, and the two antibodies showed good consistency in overall, surgical, and biopsy specimens (κ＞0.70).

The detection results of CLDN18.2 expression in gastric adenocarcinoma using the 43-14A and OTIR157B5 antibodies on the Ventana BenchMark automated immunohistochemical platform are reliable and demonstrate high consistency.