Expression Of CK7, CK8, CK14, E-cadherin, α-SMA, S100, Vimentin In Salivary Gland Pleomorphic Adenomas

Objectives: Pleomorphic adenoma (PA) is the most common salivary glandtumors in the oral and maxillofacial region. It accounts for51%of salivary glandtumors and for88%of salivary gland benign tumors. PA shows a great degree ofmorphological diversity. The essential cellular components of PA are epithelial andmyoepithelial cells, and stromal cells in myxoid and cartilaginous tissues. To investigatethe distribution and differentiation of myoepithelial cells in PA, we analyzed theexpression of CK7, CK8, CK14, E-cadherin, α-smooth muscle actin (α-SMA), S100andVimentin (Vim) in normal salivary glands and PAs.Materials and methods: This study includes66cases of PA and44cases ofnormal salivary glands obtained from the first affiliated hospital of Dalian MedicalUniversity. The samples were fixed and embedded in paraffin, and then serial paraffinsections with4μm thickness were prepared. Immunohistochemical staining wasperformed on paraffin sections using the standard streptavidin-biotin complex technique.In each case, the positive immunoreaction with antibodies against CK7, CK8, CK14,E-cadherin, α-SMA, S100and Vim was quantified by measuring the integrated opticaldensity (IOD) of the defined fields using IPP(Image pro-plus)6.0software. TheSPSS16.0statistical analysis software for Windows was used for statistical analysis.Mann Whitney U test was used to confirm comparisons of binary variables. Statisticallysignificant difference was defined as p <0.05.Results: In normal salivary glands, CK7, CK8and E-cadherin mainly expressed induct cells, while CK14and α-SMA mainly expressed in myoepithelial cells and S100only expressed in some myoepithelial cells weakly. In PA, CK7, CK8and E-cadherinmainly expressed in luminal cells; CK14, S100and Vim mainly expressed in most ofmyoepithelial cells, and α-SMA expressed in myoepithelial cells in different degrees.The expression level of CK8, CK14, α-SMA, S100and Vim in PA was significantly higher than that in normal salivary glands (p＜0.05). But the expression of CK7andE-cadherin was significantly lower than that in the controls（p＜0.05）. In the myxoidtissue of PA, S100and Vim showed strong expression, while α-SMA expressedoccasionally.Conclusions: In normal salivary gland, CK7, CK8and E-cadherin can be used asmarkers of duct cells, and CK14and α-SMA can be used as markers of myoepithelialcells. In PA, the expression of CK7, CK8and E-cadherin in luminal cells suggest theirdifferentiation towards epithelial cells; the expression of CK14, S100and Vim inmyoepithelial cells suggest their characteristics similar to mesenchymal cells.