title: High expression of claudin-1 protein in papillary thyroid tumor and its regional lymph node metastasis.
abstract: Claudins, known as major contributors in the formation of the tight junction, are differentially expressed in malignant tumors as compared to the corresponding healthy tissues. Therefore, they are thought to play a role in carcinogenesis and tumor progression. Altered expression of claudin-1 has been reported in several tumor types including endometrial, papillary renal cell and colonic carcinoma, and increased claudin-1 mRNA levels have been observed in papillary thyroid carcinoma (PTC). In this study, we aimed at determining the pattern of claudin-1 expression in various types of thyroid lesions at the protein level and investigating the immunolocalization of beta-catenin reported to regulate claudin-1 expression. Samples included 19 PTCs, ten cases of corresponding regional lymph node metastasis, eight papillary microcarcinomas (PMC), 17 follicular thyroid carcinomas (FTC) and 19 follicular adenomas (FA). All cases were evaluated by quantitative immunohistochemistry. Conspicuous claudin-1 immunostaining was detected in the majority of PTC/PMC primary tumors and lymph node metastases (19/27 and 9/10, respectively). On the other hand, we found weak or no claudin-1 expression in any of the FA and FTC cases or peritumoral non-malignant thyroid tissues. Our data prove that high claudin-1 protein expression is specific for PTC and its regional lymph node metastases, while we failed to verify that claudin-1 is regulated by beta-catenin in thyroid tumors. Based on these results, claudin-1 may be a useful tumor marker for PTC.
authors: 2nd Department of Pathology, Semmelweis University, Ulloi út 93, 1091, Budapest, Hungary.
authors: Júlia
authors: J
authors: Németh
authors: Zsuzsanna
authors: Z
authors: Németh
authors: Péter
authors: P
authors: Tátrai
authors: Ilona
authors: I
authors: Péter
authors: Aron
authors: A
authors: Somorácz
authors: Attila Marcell
authors: AM
authors: Szász
authors: András
authors: A
authors: Kiss
authors: Zsuzsa
authors: Z
authors: Schaff
mesh_terms: D000231:Adenocarcinoma, Papillary / Q000378:metabolism* / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D002648:Child; D062445:Claudin-1; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C568108:CLDN1 protein, human; D062445:Claudin-1; D008565:Membrane Proteins