Immunohistochemical investigation and study of the expression and topography of cell adhesion molecules in cases of acinic cell adenocarcinoma of salivary glands

Abstract

<h3>Background</h3> Diagnostic difficulties can arise because of the architectural diversity of acinic cell adenocarcinoma based on both growth—solid, microcystic, follicular, papillary-cystic—and cellular—acinar, intercalated ductal, vacuolated, clear and nonspecific glandular—patterns. Immunohistochemical detection systems may be helpful for the definition of the diagnosis. Cell adhesion molecules participate in tissue development and maintenance by mediating interactions between cells and extracellular matrix. E-Cadherin in epithelial adherens junctions, Dsg-2 in desmosomes, β4 integrin in hemidesmosomes, CD44s in cell-matrix interactions, and ICAM-1 are, mostly, essential for tissue integrity, architecture, and function in normal salivary gland parenchyma. <h3>Objective</h3> We used immunohistochemical methods to investigate acinic cell adenocarcinoma and to study the expression of cell adhesion molecules in order to understand the structure and the possible interactions between cellular patterns and cell-matrix in different tissue architecture. <h3>Study design</h3> Immunohistochemistry using a 2-step Envision/HRP detection system was applied to paraffin-embedded specimens of 5 acinic cell adenocarcinomas from parotid. Lobules from 7 cases of normal labial salivary glands were used as controls. Cellular profile was examined by staining with p53, Ki67, Bcl-2, A1AT, CEA, EMA, Vim, SMA, cytokeratins, GFAP, and S-100 protein. We detected cell adhesion by utilizing antibodies against CD44s, E-cadherin, β4-integrin, Dsg-2, and ICAM-1. <h3>Results</h3> p53, Ki67, and Bcl-2 positivity was associated with the degree of tumor invasion. Neoplastic epithelial cells were positive for A1TA, CEA, CKs (except CK 18), LP34 (not all cases), MNF, S-100, GFAP (locally), and Vim (basal pole). E-Cadherin and β4 integrin were positive in neoplastic epithelium only, upon cell surface (100%); Dsg-2 also was moderately positive but mainly intracellular. In a case of acinic cell adenocarcinoma all neoplastic epithelium was ICAM-1 positive. CD44s was strongly positive in all types of cells and architecture patterns. <h3>Conclusions</h3> Immunohistochemistry may be a useful tool for the diagnosis of acinic cell adenocarcinoma. On the other hand, the study of cell adhesion explains the origin of neoplastic cells and helps in the describing of the structure of different growth patterns.