Comparative expression of E-cadherin, alpha and beta catenin in salivary gland tumors

To study the expression and role of adhesion molecules in normal salivary g lands and their tumors, we have studied simultaneously the expression of E- cadherin, and associated cytoplasmic proteins, alpha-catenin and beta-caten in. Paraffin sections were evaluated using the streptavidin biotin peroxida se complex (SBPC) method for E-cadherin, and the SBPC method with tyramide signal amplification (TCA) for alpha- and beta-catenin. Normal submandibular (n = 10), parotid (n = 4) and oral minor glands (n = 4 ) showed cell membrane staining for E-cadherin and a positive reaction in i ntercalated and striated ducts for alpha- and beta-catenin. Pleomorphic ade noma (n = 17) showed cell membrane staining for E-cadherin and alpha-cateni n in luminal and non-luminal cells, but were negative for beta-catenin. E-c adherin was also focally or irregularly positive in modified myoepithelial cells. Warthin's tumors (n = 4) expressed E-cadherin only and were negative for alpha- and beta-catenins. Papillary adenocarcinoma (n = 4) showed pred ominant staining for E-cadherin, with no expression in the other tumor cell s. Adenoid cystic carcinoma (n = 4) showed only cell membrane positivity fo r E-cadherin. with an absence of alpha- and beta-catenins in the luminal ce lls. Non-luminal tumor cells of adenoid cystic carcinoma were negative for beta-cadherin and positive for alpha- and beta-catenins. The results were c oncluded as follows, 1) there was uniform cell membrane staining for E-cadh erin in normal and benign tumor epithelium, but alpha- and beta-catenins sh owed different expression and heterogeneous localization, 2) loss of E-cadh erin reactivity was seen in malignant lesions, 3) there was no correlation between the distribution of E-cadherin, alpha-catenin and beta-catenin in b enign or malignant tumors of salivary gland origins. The results show varia bility and heterogeneous expression for E-cadherin, alpha- and beta-catenin s in salivary gland tumors.