Immunohistochemical studies for oncoprotein, adhesion molecules and extracellular matrix (ECM) were carried out in oral carcinomas and salivary gland tumors.
Mutant p53 tumor suppressor gene product was found in 2 of 9 cases in epithelial displasia and 30 of 38 cases in squamous cell carcinoma (SCC) of oral mucosa. Immunohistochemical localization was confined to cell nuclei, and limited in epithelial dysplasia, and basal and parabasal area in SCC.Ratio of mutant p53 positive cells in SCC cells was correlated with malignancy of SCCs.
E-cadherin (E-cad) staining in oral SCC showed different manner with their cell differntiation. E-cad was found all cell membrane in highly differentiated SCC and negative in poorly differentiated tumor. In moderately differentiated SCC,tumor cells in central foci have positive staining and peripheral area negative. The tumor cell differntiation and the degree of E-cad expression were significantly corresponded.
During prenatal development of human salivary g
lands, laminin (LN) and type IV collagen (CL IV) were observed in the basement membrane of salivary gland duct and acini from 16-18 weeks and ataining intensity was more prominent in intermediate developing stage (19-32 weeks). The reaction products were less prominent in late development stage (33-34 weeks). Tenascin (TN) was present in epithelial-mesenchymal interface of developing salivary gland ducts from 10 weeks. In the late stage, TN was reduced around the striated ducts and negative around the intercalated ducts and acinar cells. In adult salivary gland, reaction for LN and CL IV were confined to basement membrane of ducts and acini, and TN was existed in peripheral connective tissue of striated excretory ducts. Fibronectin (FN) stained in salivary duct cells and stromal connective tissue. In pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC), modified myoepithelial cells (MMC), stained positive reaction for LN,FN,and TN.MMC may produce and secreat ECMs in myxomatou, hyalinous, and chondroidal structure of PA and those in pseudecysts of ACC.
In vitro study, human tongue carcinoma cells line (SCCKN), human salivary adenocarcinoma cell (SGT-1) and NIH3T3-3 had enhanced secretion of TN in the presence of transforming growth factor beta in a dose dependent manner and TN itself was found to possess a growth-enhancing activity. In cellular adhesion for 3 cells test suggested that all cells adhere and spread well on FN and LN,however, cells attach poorly on TN alone. When SCCKN and SGT-1 grown on FN/TN substrate induced collagenase. Enhanced TN in neoplastic lesions may have potential implications for tumor growth, differentiation, cellular adhesion, invasion and metastasis. Less