title: Claudin-4 as a marker for distinguishing malignant mesothelioma from lung carcinoma and serous adenocarcinoma.
abstract: We compared claudin-4 with Ber-EP4 and carcinoembryonic antigen as markers to distinguish mesothelioma from lung adenocarcinoma, poorly differentiated lung squamous cell carcinoma, and serous adenocarcinoma of the uterus or ovary. All mesothelioma specimens were negative for claudin-4, but 3 of 18 specimens were focally positive for Ber-EP4. In contrast, lung adenocarcinoma including poorly differentiated adenocarcinoma was highly positive for claudin-4, but expression of Ber-EP4 and carcinoembryonic antigen varied widely. Claudin-4 in poorly differentiated squamous cell carcinoma had a lower positive expression rate than in adenocarcinoma. Granular claudin-4 immunoreactivity was conspicuous in poorly differentiated squamous cell carcinoma; this immunoreactive pattern was also observed in mesothelioma. Claudin-4 was thus considered very useful marker for distinguishing mesothelioma and adenocarcinoma, even if histological specimens are small, as in biopsies that contain limited numbers of tumor cells. However, it should be mentioned that claudin-4 has a limit in discrimination between squamous cell carcinoma from mesothelioma.
authors.affiliation: 1Showa University Hospital, Tokyo, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Ohta
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Mitsuji
authors.initials: M
authors.lastname: Saito
authors.forename: Miki
authors.initials: M
authors.lastname: Kushima
authors.forename: Masafumi
authors.initials: M
authors.lastname: Takimoto
authors.forename: Akira
authors.initials: A
authors.lastname: Shiokawa
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Ota
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000378:metabolism; D062506:Claudin-4 / Q000032:analysis / Q000096:biosynthesis*; D018284:Cystadenocarcinoma, Serous / Q000175:diagnosis* / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000556:secondary; D008654:Mesothelioma / Q000175:diagnosis* / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000378:metabolism; D014594:Uterine Neoplasms / Q000175:diagnosis / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D062506:Claudin-4
keywords: Ber-EP4; carcinoembryonic antigen; carcinoma; claudin-4; malignant mesothelioma