QUANTITATION AND LOCALIZATION OF CYCLING TUMOR-CELLS IN PLEOMORPHIC ADENOMAS AND MYOEPITHELIOMAS - AN IMMUNOHISTOCHEMICAL ANALYSIS

Previous investigations have suggested that in certain salivary gland tumors only nonluminal (myoepithelial-like) tumor cells proliferate an d that this may have histogenetic implications; however, no quantitati ve assessment of the cycling component is available. We decided, there fore, to enumerate the cycling luminal and nonluminal cells in lj pleo morphic adenomas and sis myoepitheliomas by using an antibody to proli ferating cell nuclear antigen. The mean percentages of cycling luminal and nonluminal cells in pleomorphic adenomas were 2.3+/-1.4 and 2.4+/ -2.3, respectively, and 2.1+/-0.7 of the tumor cells in myoepithelioma s. Even though duct-like structures in pleomorphic adenomas are consid erably separated by more numerous nonluminal cells and, therefore, cyc ling cells may seem fewer, both cell types proliferate at similar rate s. The results indicate that nonluminal cells are not the sole prolife rative component in salivary gland tumors.