Comparative Evaluation of CD138 Expression in Pleomorphic Adenoma and Mucoepidermoid Carcinoma: An Immunohistochemical Study

Abstract

Salivary gland neoplasms are significant lesions in oral and maxillofacial pathology that exhibit diverse clinical and biological behaviors. Therefore, identifying novel markers capable of predicting the behavior of salivary gland tumors is crucial. CD138 or syndecan-1 is the primary syndecan expressed in epithelial cells and plays a critical role in tumor progression. The aim of this study was to evaluate the expression of this marker in two common salivary gland tumors. In this cross-sectional study, 20 pleomorphic adenomas (PAs) and 20 mucoepidermoid carcinomas (MECs) obtained via excisional biopsy and archived in the Pathology Departments of Al-Zahra and Ayatollah Kashani Hospitals of Isfahan University of Medical Sciences were evaluated. Clinical data including age gender of patients and anatomical location were collected. All specimens were immunohistochemically stained for syndecan-1 and the frequency and intensity of CD138 expression were calculated using the SID staining index and compared between the two tumor types. All statistical analyses were performed using SPSS version 28 employing the Mann-Whitney, Kruskal-Wallis, Chi-square, Fisher’s exact and independent t-tests. A P of<0.05 was considered statistically significant. Statistical analysis of the lesions revealed a significant difference in staining intensity between the two tumor groups (P=0.033). A statistically significant difference was observed between the PA and MEC groups based on the SID index (P=0.002). Spearman’s correlation analysis demonstrated a significant correlation between the SID index and age (P=0.007). Intermediate- and high-grade MECs showed significantly higher expression rates of CD138 (P<0.05). Increased marker expression correlated with a higher histological grade and advanced clinical stage in MECs. The use of this marker should be considered for determining the prognosis of PAs and MECs; specifically, CD138 serves as a useful prognostic predictor for MECs.