title: Reversed cellular polarity in primary cutaneous mucinous carcinoma: A study on tight junction protein expression in sweat gland tumors.
abstract: Primary cutaneous mucinous carcinoma (PCMC) is a rare sweat gland tumor characterized by the presence of abundant mucin around the tumor islands, but the molecular mechanisms for this structure are not well elucidated. Because mucin is epithelial in nature, it is likely to be produced by epithelial tumor cells, not by surrounding stromal cells. We hypothesized that the abundant mucin is a result of reversed cellular polarity of the tumor. To test this hypothesis, we conducted an immunohistological study to investigate expression of tight junction (TJ) proteins occludin and ZO-1 in PCMC, as well as in normal sweat glands and other sweat gland tumors. Dot-like or linear expression of TJ proteins was observed at ductal structures of sweat glands, and ductal or cystic structures of related tumors. In PCMC, however, TJ protein expression was clearly visible at the edges of tumor cell islands. This study provides evidence to show that the characteristic histological structure of PCMC is caused by inverse polarization of the tumor cells, and that TJ proteins are useful markers of ductal differentiation in sweat gland tumors.
authors.affiliation: Department of Dermatology, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nagasawa
authors.affiliation: Department of Dermatology, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Ishida-Yamamoto
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D062793:Occludin / Q000378:metabolism*; D013544:Sweat Gland Neoplasms / Q000378:metabolism* / Q000473:pathology; D013545:Sweat Glands / Q000166:cytology / Q000648:ultrastructure; D019108:Tight Junctions / Q000378:metabolism / Q000648:ultrastructure; D062826:Zonula Occludens-1 Protein / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C568985:OCLN protein, human; D062793:Occludin; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein
keywords: cell polarity; immunohistochemistry; mucinous adenocarcinoma; sweat gland neoplasms; tight junctions