Actin versus vimentin in myoepithelial cells of salivary gland tumors. A comparative study.

Vimentin versus actin expression was immunohistochemically studied in myoepithelial cells of 24 salivary gland tumors in which the participation of myoepithelial cells as a tumoral component has been postulated: two basal cell adenomas, seven pleomorphic adenomas, two myoepitheliomas, seven adenoid cystic carcinomas (two tubular, four cribriform, one solid), six polymorphous low-grade adenocarcinomas. Immunostaining was carried out in formalin-fixed tissue serial sections (3 microns) by the avidin-biotin method, using the antibody vimentin (Dako Corp., Carpenteria, Calif.) and the antibody HHF35 anti-muscle actin (Enzo Biochemical, N.Y.). Our results have confirmed positive staining for vimentin in all salivary tumors studied, although in some tumors it was only in focal areas. The staining for the HHF35 antibody to muscle actin was only consistently found in the adenoid cystic carcinomas of the tubular and cribriform patterns. This study suggests that actin is at least somewhat replaced by vimentin in neoplastic tumoral cells. Therefore vimentin can be used to define the participation and distribution of myoepithelial cells in these tumors.