[Figure: see text] Interleukin 25 (IL-25) is a ligand for IL-25 receptor (IL-25R) with apoptotic effect on breast cancer epithelial cells that are produced by peripheral blood mononuclear cells (PBMCs). In this study, we aimed to evaluate IL-25/IL-25R mRNA expression in PBMCs, and also investigate correlation of IL-25/IL-25R with tumor stages/grades in patients with breast cancer. PBMCs and serum were isolated from 30 patients with breast cancer and 18 normal subjects. ELISA test was conducted for IL-25 cytokine. Total RNA was isolated from 2 × 106 PBMCs and reverse transcribed to cDNA. Quantitative PCRs were performed for IL-25, IL-25R, and GAPDH genes. IL-25 mRNA expression in PBMCs of breast cancer patients (malignant and benign) was significantly lower than that in normal subjects, Also IL-25 expression in breast cancer patients with malignant tumor was significantly lower than that in nonmalignant patients. IL-25R expression in malignant patients was significantly higher than that of benign and normal subjects (P < 0.05). IL-25 in serum of normal subjects was higher than that of benign and malignant patients. There was a direct association between IL-25R expression and tumor grade/stage of cancer. In conclusion, IL-25 seems as a potential prognostic factor in the serum of breast cancer patients and reduction of IL-25 is associated with a higher grade/stage of cancer.
Keywords: IL-25; IL-25 receptor; PBMC; breast cancer; tumor grade.