Cytokeratins, smooth muscle actin and vimentin in human normal salivary gland and pleomorphic adenomas

Abstract

The distribution of immunostaining in normal major salivary gland and in 12 pleomorphic adenomas was studied using monospecific monoclonal antibodies to a number of cytokeratins, including cytokeratin 14, to smooth muscle actin and vimentin. A number of these antibodies enabled a distinction to be made between structural components of the normal gland, and to relate this to the different structures of pleomorphic adenomas. In the normal gland, the luminal duct cells expressed cytokeratins 7, 8, 18 and 19. Three antibodies were of particular value for the characterization of normal myoepithelial and basal cells; while the antibody to smooth muscle actin and the cytokeratin antibody K58.12 mutually exclusively stained the myoepithelial (basket) cells and the basal duct (light) cells, respectively, the recently established monospecific antibodies to cytokeratin 14 showed specific immunostaining with both cell types. These three antibodies left luminal cells virtually unstained. Ck 13 was found occasionally in single luminal excretory duct cells. Antibodies to cytokeratins 1/2, 10 and 10/11 did not show any staining in the normal gland. In the pleomorphic adenomas, the staining pattern of the two‐layered tubular formation resembled that of the normal gland ducts: tumour luminal cells showed the characteristic, although more irregular, expression of cytokeratins 7, 8, 18 and 19; the outer cells resembled normal ductal basal cells with their anti‐cytokeratin 14/K58.12‐epitope staining and in that they virtually lacked staining for smooth muscle actin. Trabecular formations and cells in myxoid areas were reactive with K58.12 and for cytokeratin 14, occasionally also for cytokeratins 7, 18 and 19. Epidermoid cell islets expressed mainly cytokeratin 14 and inconsistently the squamous epithelial cytokeratin 13 and the epidermal cytokeratin 10/11. Vimentin was found in cells of myxoid areas. The results support the postulate that some of the normal duct basal cells act as reserve cells and can give rise to tumour formation with a primitive myxoid or trabecular pattern and a more differentiated tubular or epidermoid configuration.

Low-grade mucoepidermoid carcinoma of salivary glands: characteristic immunohistochemical profile and evidence of striated duct differentiation

“…Results we obtained in normal ductal, luminal, basal, and myoepithelial cells are comparable to those previously obtained by Draeger et al [12]. The only difference was in the positivity for CK7 in numerous luminal acinar cells found in the present cases; Draeger et al [12] described such positivity as weak or absent. This apparent discrepancy might be explained by the use of an antigen retrieval method that probably enhanced CK7 positivity in our cases.…”

Current Thinking on Malignant Salivary Gland Neoplasms

“…Numerous studies have been carried out that have mainly focused on the cytokeratins [87], S100 [88], actins [89], epithelial membrane antigen, vimentin [89], Ca-50 [90], and carcinoembryonic antigen [90]. Unfortunately, none of these markers has proved specific or consistent enough to be reliably used in a diagnostic context [1].…”

The Main Excretory Duct (Stensen's) of the Human Parotid Gland: A Transmission and Scanning Electron Microscope Study.

“…Moreover, DARDICK et al (1988) demonstrated that the population of basal cells, in striated and excretory ducts, varies in the expression of certain cytokeratins, and suggested that not all basal cells may be considered as stem or reserve cells. In fact, it has been estimated that stem cells represent about 10% of the basal layer (POTTEN, 1979;DRAEGER et al, 1991). From a morphological point of view, we have demonstrated in this paper that basal cells are endowed with ultrastructural and three-dimensional characteristics very different from those of principal cells.…”

“…At variance with those of excretory ducts, the basal cells of the MED are arranged in an almost continuous layer. Since the basal cells are provided with abundant cytofilaments and are tightly linked to the basal lamina by very numerous hemidesmosomes, they form a supporting and protective system for the more fragile principal cells (DRAEGER et al, 1991).…”