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 saliv ary gland myoepithelial cells and ductal basal cells, respectively, were ev aluated in normal submandibular (n=4) and sublingual glands (n=3) and obstr uctive lesions of salivary glands (n=14) in humans. Immunoreactivity for CA L was observed in the normal myoepithelium in normal glands and reactive my oepithelium in the obstructive lesions. WIT immunoreactivity was seen in th e ductal basal cells but not in the myoepithelium of normal glands. During the degeneration of glandular cells in obstructive lesions, reactive myoepi thelial cells expressed both the CAL and MT. The immunoreactivity for CAL a nd MT, however, was seen in the reactive myoepithelial cells of the duct li ke 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 heterogene ity of expression of CAL and MT.