Expression and clinical significance of interleukin-9 in renal tumors

Background: To measure expression levels of interleukin-9 (IL-9) in renal tumors and to determine the clinical significance of those levels. Methods: Using TCGA database analysis, we found that the expression of IL-9 in renal clear cell carcinoma was significantly down-regulated, and was significantly related to survival. We then verified this using experiments. We enrolled 66 patients who underwent surgical resection of renal tumors between January and December 2018 at the First Affiliated Hospital of Soochow University. Their tumor tissues were paired with adjacent normal tissues and IL-9 expression levels were measured using immunohistochemistry. We determined the correlation of IL-9 expression with clinicopathological features and progression-free survival (PFS). Results: Expression of IL-9 in renal tumors was significantly lower than in adjacent normal tissues (P