An immunohistochemical study of the distribution of lysozyme, lactoferrin, alpha 1-antitrypsin and alpha 1-antichymotrypsin in salivary adenoid cystic carcinoma.

The immunohistochemical expression of lysozyme (Ly), lactoferrin (La), alpha 1-antitrypsin (alpha 1-AT), and alpha 1-antichymotrypsin (alpha 1-Ach) was described, and their distributions were compared to each other in 28 cases of adenoid cystic carcinoma (ACC) of the salivary glands. ACC materials were obtained from the parotid gland (7), the submandibular gland (4), the sublingual gland (8), and minor oral salivary glands (9). Histopathologically, ACC was classified into cribriform (14), tubular (3), and basaloid or solid patterns (11). Positive staining for Ly was found in 1 case of solid ACC in the sublingual gland; La was found in 4 cases (2 cribriform, 1 tubular, 1 basaloid) in the sublinguals (3) and parotid glands (1); alpha 1-AT was found in 6 cases and alpha 1-Ach in 17 cases. The immunohistochemical localization of Ly and La was usually confined to luminal tumor cells of tubulo-ductal structures, irrespective of the pathologic types. Positive staining for alpha 1-AT and alpha 1-Ach appeared in tumor cells of cribriform, tubular and solid ACC. Tumor cells with positive La staining coincided with a positive reaction to alpha 1-AT and alpha 1-Ach, and tumor cells with alpha 1-AT positive deposition were also positive for alpha 1-Ach. The contents of pseudocysts in the cribriform pattern showed a positive reaction to La, alpha 1-AT, and alpha 1-Ach. Of the 28 cases of ACC, positive expressions for Ly, La, alpha 1-AT and alpha 1-Ach were found with a high frequency of alpha 1-Ach staining (17 in 28 cases were positive). In sublingual ACC (8), 7 cases were positive for immunohistochemical reactions. Co-expression or simultaneous expression for Ly, La, alpha 1-AT, and alpha 1-Ach in ACC suggest that tumor cells are protected from proteolysis or degradation.