Dynamic changes of claudin 18.2 expression after systemic therapy in gastric and esophagogastric junction cancer.

Authors

Danni Zhu, Zhuoran Fang, Guangjun Jin, Jiang Chen, Yiming Lu, Teng Yang, Ke Shen, Yunfu Shi, Yuansheng Zheng, Weiwei Xu, Xiangdong Cheng, Qing Wei

Published in

Cancer. Volume 132. Issue 20. Pages e70632. Oct 15, 2026.

Abstract

Claudin 18.2 (CLDN18.2) is a promising therapeutic target in gastric/esophagogastric junction adenocarcinoma (GC/EGJC), but its dynamic expression during systemic therapy is unclear.
CLDN18.2 expression by immunohistochemistry in paired tumor samples from 155 patients with advanced GC/EGJC was retrospectively evaluated before and after systemic therapy. CLDN18.2-positive was defined as ≥75% of viable tumor cells exhibiting moderate-to-strong (2+ or 3+) membranous staining.
Among all patients, 54 (34.84%) were CLDN18.2-positive. Following treatment, the proportion of CLDN18.2-positive patients increased significantly to 61 (39.35%) (p < .001). Among patients who were CLDN18.2-negative at baseline, 57 (56.44%) showed increased expression after treatment, including 22 (21.78%) who converted to positive status. In contrast, among those CLDN18.2-positive at baseline, expression decreased in 35 patients (64.81%), with 15 (27.78%) converting to negative status (p < .001). Among patients receiving chemotherapy alone (n = 25), 1 (4.00%) converted to negative and 5 (20.00%) converted to positive, whereas among those receiving chemotherapy combined with immunotherapy (n = 130), 14 (10.77%) converted to negative and 17 (13.08%) converted to positive (p = .45). A total of 131 patients (84.52%) demonstrated changes in CLDN18.2 expression following therapy, encompassing both conversions across the positivity threshold and fluctuations within the same classification.
CLDN18.2 expression in GC/EGJC is dynamic and frequently altered after systemic therapy. These findings support reassessment of CLDN18.2 status before initiating CLDN18.2-targeted therapies.

PMID:
42845003
Bibliographic data and abstract were imported from PubMed on 08 Oct 2026.

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