Evidence map›Paper›PMID 42562621›Full record

ArticleJournal of clinical pathology2026

Retrospective analysis of Claudin 18.2 expression in 64 patients with advanced gastrointestinal peritoneal disease: a potential therapeutic target for high-grade appendiceal mucinous carcinoma.

Colman T Clarke, Ailin C Rogers, Darren Cowzer, Ann Treacy, John Aird, Meera Patel, Jurgen Mulsow, Naoimh J O'Farrell

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Article in Journal of clinical pathology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

8 authors.

Colman T ClarkeDepartment of Cellular Pathology, Mater Misericordiae University Hospital, Dublin, Ireland.
Ailin C RogersDepartment of Surgery, Mater Misericordiae University Hospital, Dublin, Ireland.
Darren CowzerSchool of Medicine, University College Dublin - National University of Ireland, Dublin, Ireland.
Ann TreacyDepartment of Cellular Pathology, Mater Misericordiae University Hospital, Dublin, Ireland.
John AirdDepartment of Cellular Pathology, Mater Misericordiae University Hospital, Dublin, Ireland.
Meera PatelDepartment of Surgery, Mater Misericordiae University Hospital, Dublin, Ireland.
Jurgen MulsowDepartment of Surgery, Mater Misericordiae University Hospital, Dublin, Ireland.
Naoimh J O'FarrellDepartment of Cellular Pathology, Mater Misericordiae University Hospital, Dublin, Ireland nofarrell@mater.ie.ORCID http://orcid.org/0000-0003-0247-6953

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

aimsSpecific to normal gastric epithelium, Claudin 18.2 (CLDN18.2) is a tight junction protein. CLDN18.2 immunohistochemistry is a companion diagnostic used to identify oesophageal and gastric adenocarcinoma patients eligible for targeted therapy with zolbetuximab. It has demonstrated survival benefits in advanced upper gastrointestinal (UGI) cancers, with many studies now exploring its potential use beyond the UGI tract. This study aimed to examine CLDN18.2 expression in a peritoneal malignancy patient cohort.

methodsCLDN18.2 immunohistochemistry was performed on archived tissue from patients who underwent cytoreductive surgery at a national centre for peritoneal malignancy. CLDN18.2 immunoprofiles were compared in two key tumour cohorts: peritoneal metastases from colorectal adenocarcinoma and appendiceal mucinous neoplasms. Positivity was defined as moderate-to-strong membranous staining in

results64 cases were examined; primary tumour sites of origin were colorectal (n=34, 53%) and appendiceal (n=30, 47%). CLDN18.2 positivity in the overall appendiceal group was 17% compared with 3% in colorectal adenocarcinomas (p=0.090). In the appendiceal group, CLDN18.2 positivity was only demonstrated in high-grade appendiceal mucinous carcinomas (22%, 5 of 23). CLDN18.2 positive staining (>0% of tumour cells) was significantly increased in the appendiceal group compared with colorectal adenocarcinoma (53% vs 3%, respectively) (p<0.0001).

conclusionsThese results demonstrate CLDN18.2 expression in a subset of appendiceal peritoneal metastases. This is one of the first focused studies showing CLDN18.2 expression in this tumour group, perhaps highlighting a future role for targeted therapies in those with limited curative oncological options.

Indexed as

Adenocarcinoma, MucinousAppendiceal NeoplasmsBiomarkers, TumorClaudinsColorectal NeoplasmsPeritoneal NeoplasmsAdultAgedAged, 80 and overFemaleHumansImmunohistochemistryMaleMiddle AgedNeoplasm GradingRetrospective StudiesBiomarkers, TumorClaudinsCLDN18 protein, humanBiomarkers, TumorGastrointestinal NeoplasmsPathology, Molecular

Identifiers

PMID42562621
PMCPMC13638285

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