Heterogeneity and co-expression of intermediate filament proteins in adenoid cystic carcinoma of salivary glands.

Among a series of 76 adenoid cystic carcinomas (ACC), 51 cases with cibriform or trabecular patterns were selected for an immunohistochemical study. These tumors were composed of three types of cells: basaloid, myoepithelial and ductal luminal acinous or tubular cells with a variable amount of each cell type from one case to another. Monoclonal antibodies (MoAb) against keratins (PKK1, KL1, K8.12, K8.13, K4.62 anti-cytokeratins antibodies) and against vimentin were used. Tubular cells were characteristically marked by anti-cytokeratins MoAb, but with a great heterogeneity of keratin distribution. In myoepithelial cells, keratin was absent or slightly positive and vimentin was present, with co-expression of the two types of filaments in some cells. Like myoepithelial cells, basaloid cells were positive to anti-vimentin antibody and negative or slightly positive to anti-keratin antibodies, with sometimes a co-expression of vimentin and keratin filaments in the same cell. Histogenesis of adenoid cystic carcinomas was discussed. Progenitor intercalated duct reserve cells may change into ductal luminal and myoepithelial tumor cells. Otherwise, basaloid cells, arising also from intercalated duct reserve cells, are able to acquire some secretory organites.