title: Expression and cellular localization of TSC-22 in normal salivary glands and salivary gland tumors: implications for tumor cell differentiation.
abstract: TGF-beta-stimulated clone-22 (TSC-22) was reported to be a differentiation-inducing factor which negatively regulates the growth of salivary gland cancer cells. In the present study, we examined the expression of TSC-22 in salivary gland tumors by immunohistochemistry. In pleomorphic adenoma (PA), most of the sparse myoepithelial-like tumor cells, which are considered as the differentiated cells because they produce extracellular matrix, expressed TSC-22. However, only a limited number of cases of the solid myoepithelial-like tumor cells in PA, which are considered as the growing cells, expressed TSC-22. In adenoid cystic carcinoma (ACC), inner ductal cells in the tubular structure, strongly expressed TSC-22, though the outer myoepithelial-like tumor cells did not express TSC-22. In the cribriform structure, myoepithelial-like tumor cells did not express TSC-22. However, a small ductal structure in the micro-cyst wall strongly expressed TSC-22. Sparse type myoepithelial-like tumor cells in ACC also expressed TSC-22. In mucoepidermoid carcinoma, epidermoid tumor cells and mucous-producing tumor cells in mucoepidermoid carcinoma frequently expressed TSC-22. Thus, the expression of TSC-22 was frequently observed in the cells with differentiated-phenotypes, although rarely in the cells with growing potentials. These results suggest that TSC-22 may play an important role in maintaining the differentiated phenotype in salivary gland tumors.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Doi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kawamata
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ono
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujimori
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Imai
mesh_terms: D002454:Cell Differentiation; D006801:Humans; D007150:Immunohistochemistry; D012097:Repressor Proteins / Q000032:analysis / Q000378:metabolism*; D012468:Salivary Gland Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D012469:Salivary Glands / Q000737:chemistry / Q000378:metabolism*
chemical_list: D012097:Repressor Proteins; C099726:TSC22D1 protein, human