Phosphorylated signal transducer and activator of transcription 1 is a potential predictor of interferon response in patients with advanced renal cell carcinoma.

The present study aimed to evaluate the expression status of Janus kinase (JAK)-Signal Transducer and Activator of Transcription (STAT) in renal cell carcinoma and benign renal tissue, and identify a potential biomarker for interferon (IFN) response prediction. A total of 32 specimens of human renal cell carcinoma and 10 specimens of benign renal tissue were harvested from surgically removed kidneys. The expression levels of JAK‑STAT were determined by immunohistochemical staining and quantitative polymerase chain reaction. Furthermore, the expression levels of JAK‑STAT in renal cell carcinoma tissues that were stimulated with IFN-α were quantified by western blot analysis. The positive expression rates of JAK1, STAT1 and phosphorylated (P)‑STAT1 in the renal cell carcinomas were significantly lower than that in the benign renal tissues (25.0, 31.2, and 12.5% vs. 70.0, 50.0, and 70.0%, respectively; P<0.05). The relative expression levels of JAK1 (0.696 ± 0.102) and STAT1 mRNA (0.341 ± 0.068) in the tumor tissue were lower than those in the benign tissue (0.957 ± 0.103 and 0.547 ± 0.082, respectively; P<0.05). IFN stimulation enhanced the expression levels of P‑STAT1 in the renal cell carcinoma tissues, and enhancement of the P‑STAT1 expression levels was associated with tumor relapse and metastasis. In conclusion, P‑STAT1 is a potential predictor of IFN response in patients with advanced renal cell carcinoma.