MicroRNAs expression pattern related to mast cell activation and angiogenesis in paraffin-embedded salivary gland tumors.

The aim of this study was evaluate the expression profile of microRNAs related to mast cells activation and angiogenesis in salivary glands tumors. Method. We have analyzed the expression of miR-9, miR-16, miR-17, miR-132, miR-195 and miR-221 by real-time RT-PCR, in 11 adenoid cystic carcinomas, 9 mucoepidermoid carcinomas and 11 pleomorphic adenomas. Immunohistochemical investigation was performed to detect mast cells tryptase and CD-34 for microvessels biomarkers. miR-16, miR-17, miR-132, miR-195 and miR-221 showed a decreased expression, whereas miR-9 showed an increased expression in most cases compared to normal tissues. However, in all tumors studied only miR-9 showed a statistical significant negative correlation with microvessel density (p=0.001). It was observed a higher density of mast cells in mucoepidermoid carcinomas (10.55 cells/mm2) when compared to adenoid cystic carcinomas (6.27 cells/mm2) and between mucoepidermoid carcinomas and pleomorphic adenomas (5.97células/mm2). miR-17, miR-132, miR-195 and miR-221 seem to play an important role as tumor suppressor in salivary gland tumors. In addition, the significant correlation between mast cell and microvessel density contributes to the growth and pathogenesis of these tumors and they may become strong therapeutic targets in the future.