{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,18]],"date-time":"2026-05-18T10:08:40Z","timestamp":1779098920366,"version":"3.51.4"},"reference-count":35,"publisher":"BMJ","issue":"6","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["J Clin Pathol"],"accepted":{"date-parts":[[2026,3,21]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>Aims<\/jats:title>\n                    <jats:p>Malignant effusion is a common manifestation of metastatic gastric cancer. This study compared the expression of key biomarkers (human epidermal growth factor receptor 2 (HER2), programmed cell death ligand 1 (PD-L1), claudin 18.2 (CLDN18.2) and fibroblast growth factor receptor 2b (FGFR2b)) between malignant effusion-derived cell blocks (CBs) and matched primary or metastatic tumour tissues and evaluated the longitudinal concordance of biomarker expression in serially collected CBs.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Biomarker status was retrospectively assessed by immunohistochemistry in CBs from malignant effusions and paired primary\/metastatic gastric adenocarcinomas. HER2+ cases underwent fluorescence in situ hybridisation to confirm amplification.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>CLDN18.2 showed the highest positivity rate (34.0%). PD-L1 expression was positive in 8.6% of tumours and 13.9% of stroma. Lower rates were observed for FGFR2b (3.8%) and HER2 (3.3%). FGFR2b positivity was more frequent in CBs than in primary tumours (p=0.044) with higher expression levels (p=0.02). Conversely, CLDN18.2 positivity was lower in CBs versus primary tumours (p=0.004). Metastatic lesions showed higher CLDN18.2 positivity (p=0.04) and expression levels (p=0.002) compared with CBs. Serial CB analysis revealed high concordance rates: FGFR2b (99.1%), HER2 (98.1%), tumour PD-L1 (94.8%) and CLDN18.2 (92.2%).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Malignant effusion CBs show favourable intra-patient biomarker consistency over time, supporting their feasibility for longitudinal monitoring. Effusion-based testing shows potential value for potentially identifying candidates for FGFR2b-targeted therapies, pending further clinical validation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/jcp-2026-210622","type":"journal-article","created":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T17:20:29Z","timestamp":1775150429000},"page":"410-417","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Malignant effusions serve as a feasible source for therapy-related biomarker testing in advanced gastric cancer"],"prefix":"10.1136","volume":"79","clinical-trial-number":[{"clinical-trial-number":"nct03694522","registry":"10.18810\/clinical-trials-gov"}],"author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3903-0541","authenticated-orcid":false,"given":"Wenhao","family":"Ren","sequence":"first","affiliation":[{"name":"Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qian","family":"Wang","sequence":"additional","affiliation":[{"name":"Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yiyi","family":"Guo","sequence":"additional","affiliation":[{"name":"Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Haizhu","family":"Jin","sequence":"additional","affiliation":[{"name":"Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiuli","family":"Ma","sequence":"additional","affiliation":[{"name":"Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yanli","family":"Zhu","sequence":"additional","affiliation":[{"name":"Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2026,4,2]]},"reference":[{"key":"2026051802151035000_79.6.410.1","doi-asserted-by":"publisher","DOI":"10.3322\/CAAC.21834"},{"key":"2026051802151035000_79.6.410.2","first-page":"122","article-title":"Advanced gastric cancer in jordan from 2004 to 2008: a study of epidemiology and outcomes","volume":"4","author":"Abbasi","year":"2011","journal-title":"Gastrointest Cancer Res"},{"key":"2026051802151035000_79.6.410.3","doi-asserted-by":"publisher","DOI":"10.1002\/ijc.28373"},{"key":"2026051802151035000_79.6.410.4","doi-asserted-by":"publisher","DOI":"10.1007\/s10120-011-0085-6"},{"key":"2026051802151035000_79.6.410.5","doi-asserted-by":"crossref","first-page":"1213","DOI":"10.1097\/PAS.0000000000001779","article-title":"Human Leukocyte Antigen Class I Deficiency in Gastric Carcinoma: An Adaptive Immune Evasion Strategy Most Common in Microsatellite Instable Tumors","volume":"45","author":"Iwasaki","year":"2021","journal-title":"Am J Surg Pathol"},{"key":"2026051802151035000_79.6.410.6","doi-asserted-by":"publisher","DOI":"10.1016\/S1470-2045(22)00603-9"},{"key":"2026051802151035000_79.6.410.7","doi-asserted-by":"publisher","DOI":"10.1007\/s10120-014-0394-7"},{"key":"2026051802151035000_79.6.410.8","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejca.2012.10.018"},{"key":"2026051802151035000_79.6.410.9","doi-asserted-by":"publisher","DOI":"10.3748\/wjg.v22.i26.5879"},{"key":"2026051802151035000_79.6.410.10","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.ejca.2015.09.018","article-title":"Extra-gain of HER2-positive cases through HER2 reassessment in primary and metastatic sites in advanced gastric cancer with initially HER2-negative primary tumours: Results of GASTric cancer HER2 reassessment study 1 (GASTHER1)","volume":"53","author":"Park","year":"2016","journal-title":"Eur J Cancer"},{"key":"2026051802151035000_79.6.410.11","doi-asserted-by":"publisher","DOI":"10.1007\/s10120-018-0887-x"},{"key":"2026051802151035000_79.6.410.12","doi-asserted-by":"publisher","DOI":"10.1007\/s10120-024-01505-6"},{"key":"2026051802151035000_79.6.410.13","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0074757","article-title":"Down-regulation of claudin-18 is associated with the proliferative and invasive potential of gastric cancer at the invasive front","volume":"8","author":"Oshima","year":"2013","journal-title":"PLoS One"},{"key":"2026051802151035000_79.6.410.14","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijsu.2013.11.022"},{"key":"2026051802151035000_79.6.410.15","doi-asserted-by":"crossref","first-page":"67","DOI":"10.21037\/jgo-24-743","article-title":"Expression of Claudin18.2 in metastatic lesions in peritoneum of gastric cancer","volume":"16","author":"Saito","year":"2025","journal-title":"J Gastrointest Oncol"},{"key":"2026051802151035000_79.6.410.16","doi-asserted-by":"publisher","DOI":"10.1093\/jjco\/hyz068"},{"key":"2026051802151035000_79.6.410.17","doi-asserted-by":"crossref","DOI":"10.1038\/s41598-024-68411-w","article-title":"Heterogeneity of claudin 18.2 expression in metastatic gastric cancer","volume":"14","author":"Choi","year":"2024","journal-title":"Sci Rep"},{"key":"2026051802151035000_79.6.410.18","doi-asserted-by":"crossref","DOI":"10.1038\/s41598-021-84107-x","article-title":"Clinical difference between fibroblast growth factor receptor 2 subclass, type IIIb and type IIIc, in gastric cancer","volume":"11","author":"Yashiro","year":"2021","journal-title":"Sci Rep"},{"key":"2026051802151035000_79.6.410.19","doi-asserted-by":"crossref","DOI":"10.1200\/PO-24-00710","article-title":"Prevalence of FGFR2b Protein Overexpression in Advanced Gastric Cancers During Prescreening for the Phase III FORTITUDE-101 Trial","volume":"9","author":"Rha","year":"2025","journal-title":"JCO Precis Oncol"},{"key":"2026051802151035000_79.6.410.20","doi-asserted-by":"crossref","first-page":"598","DOI":"10.1007\/s10120-025-01611-z","article-title":"Low positivity rate of fibroblast growth factor receptor 2b is associated with heterogeneous expression in gastric cancer","volume":"28","author":"Lee","year":"2025","journal-title":"Gastric Cancer"},{"key":"2026051802151035000_79.6.410.21","doi-asserted-by":"crossref","unstructured":"Ogawa H , Abe H , Yagi K , et al . Spatial heterogeneity of FGFR2b in gastric cancer: a comparative analysis of primary tumors and peritoneal dissemination. Virchows Arch 2025. doi:10.1007\/s00428-025-04233-z","DOI":"10.1007\/s00428-025-04233-z"},{"key":"2026051802151035000_79.6.410.22","doi-asserted-by":"publisher","DOI":"10.1038\/modpathol.2016.96"},{"key":"2026051802151035000_79.6.410.23","doi-asserted-by":"crossref","DOI":"10.25259\/Cytojournal_40_2023","article-title":"Diagnostic analysis of pleural fluid cell blocks using relevant immunohistochemical markers in clinically suspicious cases of malignancy","volume":"21","author":"Mathew","year":"2024","journal-title":"Cytojournal"},{"key":"2026051802151035000_79.6.410.24","doi-asserted-by":"publisher","DOI":"10.1111\/apm.1965.64.1.31"},{"key":"2026051802151035000_79.6.410.25","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2559.2008.03028.x"},{"key":"2026051802151035000_79.6.410.26","doi-asserted-by":"publisher","DOI":"10.1007\/s00428-010-0952-2"},{"key":"2026051802151035000_79.6.410.27","doi-asserted-by":"publisher","DOI":"10.1016\/s0140-6736(23)00620-7"},{"key":"2026051802151035000_79.6.410.28","doi-asserted-by":"publisher","DOI":"10.1038\/s41591-023-02465-7"},{"key":"2026051802151035000_79.6.410.29","doi-asserted-by":"publisher","DOI":"10.1136\/jcp.48.9.876"},{"key":"2026051802151035000_79.6.410.30","doi-asserted-by":"publisher","DOI":"10.21147\/j.issn.1000-9604.2024.01.08"},{"key":"2026051802151035000_79.6.410.31","doi-asserted-by":"crossref","DOI":"10.3390\/medicina61091675","article-title":"The Effect of HER2 Status on Gastric Cancer Survival and the Clinical Implications of the HER2-Low Definition: A Retrospective Study","volume":"61","author":"Uzun","year":"2025","journal-title":"Medicina (Kaunas)"},{"key":"2026051802151035000_79.6.410.32","doi-asserted-by":"crossref","DOI":"10.3390\/cancers12082318","article-title":"The Clinicopathological Characteristics And Genetic Alterations of Signet-ring Cell Carcinoma in Gastric Cancer","volume":"12","author":"Huang","year":"2020","journal-title":"Cancers (Basel)"},{"key":"2026051802151035000_79.6.410.33","doi-asserted-by":"crossref","first-page":"303","DOI":"10.5230\/jgc.2025.25.e2","article-title":"Discordance in Claudin 18.2 Expression Between Primary and Metastatic Lesions in Patients With Gastric Cancer","volume":"25","author":"Son","year":"2025","journal-title":"J Gastric Cancer"},{"key":"2026051802151035000_79.6.410.34","doi-asserted-by":"crossref","first-page":"112710","DOI":"10.1016\/j.isci.2025.112710","article-title":"Evolution of HER2 expression after neoadjuvant therapy in locally advanced gastric cancer","volume":"28","author":"He","year":"2025","journal-title":"iScience"},{"key":"2026051802151035000_79.6.410.35","doi-asserted-by":"crossref","first-page":"1378","DOI":"10.1016\/j.medj.2024.07.006","article-title":"Tumor microenvironment RNA test to predict immunotherapy outcomes in advanced gastric cancer: The TIMES001 trial","volume":"5","author":"Shi","year":"2024","journal-title":"Med"}],"container-title":["Journal of Clinical Pathology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/jcp-2026-210622","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,18]],"date-time":"2026-05-18T09:16:14Z","timestamp":1779095774000},"score":1,"resource":{"primary":{"URL":"https:\/\/jcp.bmj.com\/lookup\/doi\/10.1136\/jcp-2026-210622"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,2]]},"references-count":35,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,5,18]]},"published-print":{"date-parts":[[2026,6]]}},"alternative-id":["10.1136\/jcp-2026-210622"],"URL":"https:\/\/doi.org\/10.1136\/jcp-2026-210622","relation":{},"ISSN":["0021-9746","1472-4146"],"issn-type":[{"value":"0021-9746","type":"print"},{"value":"1472-4146","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,2]]}}}