ArticleVirchows Archiv : an international journal of pathology2025
Concordance of laboratory assays for claudin 18.2 in gastric cancer tissue samples: independent proficiency testing and a descriptive non-interventional study.
Article in Virchows Archiv : an international journal of pathology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
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Who cites it
4 citing papers in PubMed.
- Claudin 18.2 expression-concordance between primary and metastatic lesions in gastric and gastroesophageal adenocarcinomas: a systematic review and meta-analysis.ESMO gastrointestinal oncology · 2026Review
- [Biomarker testing for carcinomas of the upper gastrointestinal tract].Pathologie (Heidelberg, Germany) · 2026Review
- CLDN18.2-Directed Therapeutics in Gastric and Gastroesophageal Junction Adenocarcinoma: Biomarker Assessment, Expression Dynamics, and Treatment Sequencing.Cancer management and research · 2026Review
- Resistance mechanisms and countermeasures in CLDN18.2-positive tumors: from molecular networks to clinical practice.Frontiers in oncology · 2026Review
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8 authors.
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Abstract
Biomarker testing is vital for personalized cancer treatment with improved efficacy based on genotype and biomarker expression. This prospective, in vitro, non-interventional study accompanied an independent proficiency test to descriptively analyze the results of immunohistochemical claudin 18.2 (CLDN18.2) testing in gastric cancer tissue samples by laboratories in Germany, Austria, and Switzerland, using assays independently established in their institutions. CLDN18.2 is a biomarker and drug target for locally advanced unresectable/metastatic gastric and pancreatic cancer. During an open proficiency test (OPT), laboratories were provided with 10 gastric cancer tissue samples (cases) for staining, interpretation, and scoring by a pathologist. Results were submitted with stained tumor cell percentage and a binary CLDN18.2-positive/negative result for each sample (cut-off: ≥ 75% of tumor cells expressing membranous CLDN18 with ≥ 2+ [moderate to strong] staining intensity). Successful participation was defined as ≥ 90% of cases evaluated correctly. Overall proficiency of the OPT was acceptable if ≥ 80% of laboratories participated successfully. Fifty-four institutes registered for the OPT, and one resigned. Forty-two of 53 (79.2%) institutes participated successfully. The main source of errors was false negative results (false negative rate, 12%; false positive rate, 1%). Overall accuracy was 91%. The CLDN18 (43-14A) clone was used most frequently, with optimal staining results and minor interpretation problems observed. Two antibodies were associated with false negative results (ZR451 [Zeta/Zytomed]; EPR19202 [Abcam]). Staining quality was the major factor for successful analysis; interpretation errors were not significant. Ongoing quality assurance will enable establishment of appropriate staining protocols and accurate CLDN18.2 interpretation, thereby facilitating individually optimized treatment.
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