EXPRESSION OF THE ADENOCARCINOMA-RELATED ANTIGEN RECOGNIZED BY MONOCLONAL-ANTIBODY 44-3A6 IN SALIVARY-GLAND NEOPLASIAS

The monoclonal antibody 44-3A6 detects a cell-surface protein that has been shown to be a useful marker in distinguishing adenocarcinomas fr om other histologic tumor types in a variety of tissues. The objective of this study was to determine whether 44-3A6 could be used as a tool in the classification of salivary gland neoplasms. These complex tumo rs share overlapping pathologic features but distinct clinical outcome s, This study used 44-3A6 to immunohistochemically describe the patter n and frequency of this antigen in salivary gland neoplasms. Formalin- fixed, paraffin-embedded tissue sections of 22 benign and 26 malignant salivary tumors were evaluated. The patient population consisted of 2 5 (52.1%) women and 23 (47.9%) men selected from archival pathology fi les to reflect a range of salivary gland diseases. Normal surrounding salivary glands were found to have intense focal staining almost exclu sively localized to ductal luminal cells. There was little staining of either myoepithelial or acinar cells. A wide spectrum of expression w as found between and within tumor types, but a trend toward more expre ssion of this antigen with decreasing differentiation was seen. A sign ificant increase in staining was also seen in those tumors with ductal differentiation (n = 41) as opposed to those with predominantly acina r (i.e., acinic cell carcinoma) or myoepithelial (i.e., myoepithelioma ; n = 8) differentiation (2.6 vs. 1.3, p < 0.05), No correlation was f ound between staining intensity and facial paralysis, pain, skin invol vement, TNM stage, residual disease, or disease-free or total survival , Therefore this antigen appears to designate a duct luminal phenotype in normal and neoplastic salivary tissues.