Investigation of IL-33 serum levels in patients with benign and malignant salivary gland tumors

Interleukin-33 (IL-33) has been recently discovered as an influential factor in the process of tumor immunity, and is presented in cancer pathogenesis. This study aimed to determine the serum levels of IL-33 in patients with benign and malignant Salivary gland tumors (SGTs). This descriptive cross-sectional study was performed on 47 samples of malignant SGTs including 18 mucoepidermoid carcinoma (MEC), 8 adenoid cystic carcinoma (ADCC), 21 malignant mixed tumor (MMT), and 14 benign pleomorphic adenoma (PA). A control group was considered consisting of 28 healthy subjects. The serum level of IL-33 was measured by using sandwich ELISA method. The data were statistically analyzed through Kruskal-Wallis and Mann-Whitney tests. The median concentration of IL-33 was 6.91 in malignant, 5.14 in benign, and 5.01 in healthy cases, with a statistically significant difference (P= 0.001). The median serum levels of IL-33 increased significantly in ADCC (7.15), MEC (7.03), and MMT (6.91) compared with the control group (5.01) (P< 0.05). The mean rank of MEC was significantly higher than PA (P= 0.01). IL-33 concentration was positively and significantly correlated with the tumor stage (P= 0.02) and tumor size (P= 0.03). IL-33 could be suggested as a novel biomarker to distinguish different types of SGTs.