Immunohistochemical demonstration of lysozyme and lactoferrin in salivary pleomorphic adenomas

MUC1 and Polarity Markers INADL and SCRIB Identify Salivary Ductal Cells

Current treatments for xerostomia/dry mouth are palliative and largely ineffective. A permanent clinical resolution is being developed to correct hyposalivation using implanted hydrogel-encapsulated salivary human stem/progenitor cells (hS/PCs) to restore functional salivary components and increase salivary flow. Pluripotent epithelial cell populations derived from hS/PCs, representing a basal stem cell population in tissue, can differentiate along either secretory acinar or fluid-transporting ductal lineages. To develop tissue-engineered salivary gland replacement tissues, it is critical to reliably identify cells in tissue and as they enter these alternative lineages. The secreted protein α-amylase, the transcription factor MIST1, and aquaporin-5 are typical markers for acinar cells, and K19 is the classical ductal marker in salivary tissue. We found that early ductal progenitors derived from hS/PCs do not express K19, and thus earlier markers were needed to distinguish these cells from acinar progenitors. Salivary ductal cells express distinct polarity complex proteins that we hypothesized could serve as lineage biomarkers to distinguish ductal cells from acinar cells in differentiating hS/PC populations. Based on our studies of primary salivary tissue, both parotid and submandibular glands, and differentiating hS/PCs, we conclude that the apical marker MUC1 along with the polarity markers INADL/PATJ and SCRIB reliably can identify ductal cells in salivary glands and in ductal progenitor populations of hS/PCs being used for salivary tissue engineering. Other markers of epithelial maturation, including E-cadherin, ZO-1, and partition complex component PAR3, are present in both ductal and acinar cells, where they can serve as general markers of differentiation but not lineage markers.

Immunohistochemical Detection of Salivary Agglutinin/gp-340 in Human Parotid, Submandibular, and Labial Salivary Glands

Salivary agglutinin is a Streptococcus mutans binding protein and a member of the scavenger receptor cysteine-rich superfamily. It is identical to lung gp-340 and brain DMBT1, which possibly play a role in innate immunity and tumor suppression, respectively. The goal of this study was to localize salivary agglutinin in human salivary glands. Two monoclonal antibodies, directed against gp-340, were characterized. mAb 213-1 reacted with sialic acid epitopes and cross-reacted with MUC7. The reaction with mAb 213-6 disappeared after reduction, suggesting that a protein epitope was recognized. In the parotid gland, immunohistochemical labeling with mAb 213-6 was found in the duct cells. In the submandibular gland and labial gland, both serous acini and demilune cells were labeled. In the labial gland, labeling was found at the luminal side of the duct cells. Salivary agglutinin was distinctly localized in salivary glands, but in distinct glandular secretions, no differences in electrophoretic behavior were observed.

Functional Histology of Salivary Gland Pleomorphic Adenoma: An Appraisal

The complex microstructure of salivary gland pleomorphic adenoma is examined in relation to function. Events related to secretion of macromolecules and absorption, responses to the altered microenvironment and controversies concerning epithelial-mesenchymal transition versus modified myoepithelial differentiation are explored. Their effects on tumor cell phenotypes and arrangements are emphasized. Heterotopic differentiation and attempts at organogenesis are also considered. The approach allows interpreting microstructure independently of histogenetic perceptions, envisaging the tumor cells as a continuum, endorsing luminal structures as the principal components, and defining pleomorphic adenoma as a benign epithelial tumour characterized by variable epithelial-mesenchymal transition, secretion/differentiation and metaplasia.

Lactoferrin in human tumours: immunohistochemical investigations during more than 25 years

Lactoferrin (LF) is an iron-binding glycoprotein of the transferrin family, today known to have multifunctional physiological activities. In humans, under normal conditions, LF has been found in blood, mucosal secretions, gastrointestinal fluids, urine and mostly in milk and colostrum. The first pioneering immunohistochemical report about LF distribution in human tissues dated in 1978; successively, many studies have been performed to analyze the LF immunohistochemical pattern in different normal and neoplastic tissues. In this review, we present data from literature concerning the evidence of LF in tumors together with those by us obtained during more than 25 years; the immunohistochemical applications to human neoplastic tissues have been done to investigate the LF pathogenetic role as well as its activity in cancer. After a systematic analysis of LF immunoreactivity in different human districts, a possible explanation for its presence and function has been modulated for each site or tissue, according to experimental evidences obtained either by in vivo as well as by in vitro studies.

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.

Immunohistochemical localization of lysozyme, lactoferrin, alpha 1-antichymotrypsin, and alpha 1-antitrypsin in salivary gland of human fetuses

26 human fetuses were examined to elucidate the immunohistochemical distributions of lysozyme, lactoferrin, alpha 1-antichymotrypsin, and alpha 1-antitrypsin in prenatal salivary glands. Development of fetal salivary glands was divided into 4 stages: The early developmental stage (EDS), the early intermediate developmental stage (EIDS), the late intermediate developmental stage (LIDS), and the late developmental stage (LDS) and were used to compare antigen localization during salivary gland development. Lysozyme (LY) staining was prominent in serous or demilune cells of the mucous acinar compartment. Lactoferrin (LF) was rarely seen in the fetal glands; only trace amounts were seen in serous cells, alpha 1-antichymotrypsin (alpha 1-ACT) was diffusely positive particularly in glandular ducts, alpha 1-antitrypsin (alpha 1-AT) was also diffusely distributed in all salivary gland elements and was more abundant in ductal cells than acinar cells. During the EDS, immunohistochemical staining of LY, LF, alpha 1-ACT, and alpha 1-AT could be observed with glandular intensity increases corresponding to the advance of cytodifferentiation of granular epithelium occurring in the subsequent EIDS and LIDS. Staining intensities were continuous during the LDS even though the amount of those materials in the fetal salivary glands was not of the extent seen in the adult salivary gland. These results suggest that production of LY, LF, alpha 1-ACT, and alpha 1-AT was positive during prenatal development of human salivary glands. The present study discusses the protective roles and defense mechanisms of LY, LF, alpha 1-ACT, and alpha 1-AT in developing human salivary glands.