Heterogeneity of Expression of Calponin and Metallothionein in Reactive Myoepithelial/Ductal Basal Cells of Obstructive Sialadenitis.

The expression of calponin(CAL) and metallothionein(MT), markers of salivary gland myoepithelial cells and ductal basal cells, respectively, were evaluated in normal submandibular(n=4) and sublingual glands(n=3) and obstructive lesions of salivary glands(n=14) in humans. Immunoreactivity for CAL was observed in the normal myoepithelium in normal glands and reactive myoepithelium in the obstructive lesions. MT immunoreactivity was seen in the ductal basal cells but not in the myoepithelium of normal glands. During the degeneration of glandular cells in obstructive lesions, reactive myoepithelial cells expressed both the CAL and MT. The immunoreactivity for CAL and MT, however, was seen in the reactive myoepithelial cells of the duct like structures in the fibrotic glands during the late stages of obstructive lesions. The results of the present study reasonably allowed us to suggest that the reactive myoepithelial cells in obstructive salivary gland lesions may demonstrate cellular characteristics of both the myoepithelial/ductal basal cells of normal salivary glands with respect to phenotypic heterogeneity of expression of CAL and MT.