Immunohistochemical Analysis of Endocan Expression in Salivary Pleomorphic Adenoma

Background: The tumors of salivary glands make up ۳% of neoplasms in the head and neck region. Pleomorphic adenoma (PA) represents the most prevalent benign tumor of the salivary glands. Endocan is secreted by endothelial cells and is associated with tumorigenesis/tumor progression. This study aimed to analyze the expression and distribution pattern of endocan in salivary PA and the contribution of markers to tumor development. Methods: Overall, ۳۵ PA samples from parotid glands were collected from the Archive of the Pathology Department of Educational Hospital from ۲۰۱۶ to ۲۰۲۱. Hematoxylin and eosin staining confirmed the previous diagnosis. All samples were classified based on the differentiation of epithelial cells and the amount of the stroma according to the Seifert et al classification. Then, the specimens were processed for immunohistochemistry (IHC) analysis. Results: Based on the Seifert et al classification, ۳۷% of PAs were classified as classic type. The cellular or myxoid type was found in ۳۱.۴% of cases (each with ۱۱ cases). There was a significant difference between the age of the patients and the histological subtype (P<۰.۰۱۱). Additionally, a statistically significant difference was found between the duration of the tumor and the histological subtypes (P<۰.۰۱۸). Endocan positivity was mainly observed in the ductal epithelium in the classic subtype. Moreover, plasmacytoid-like and spindle cells were stained for endocan primarily in the classic type. Conclusion: The present study demonstrated a noticeable occurrence of endocan positivity in different cell types found in PA samples. The findings from our research offer evidence that supports the notion that endocan is crucial in the progression and potentially in the malignant transformation of PAs. The immunoreactivity shown by plasmacytoid-like and spindle cells provides a strong indication of the possible presence of the epithelial-mesenchymal transition phenomenon as a key factor in the development of these tumors. Thus, endocan can be considered a potential therapeutic target for PA.