Prognostic and predictive role of intra-tumoral CXCR1 expression in patients receiving tyrosine kinase inhibitors for metastatic clear-cell renal cell carcinoma

Objective: We aimed to evaluate the role of intra-tumoral CXCR1 expression in predicting prognosis and treatment response in metastatic clear-cell renal cell carcinoma patients receiving tyrosine kinase inhibitors. Materials and methods: Patients with metastatic clear-cell renal cell carcinoma presented between February 2018-December 2019 were studied for the CXCR1 expression in tumor tissues before starting tyrosine kinase inhibitors. Primary outcome measure was progression-free survival. Secondary outcome measures included overall survival and prediction of treatment response. Results: The study included 35 patients with a mean age of 53.6 +/- 9.6 years. At a mean follow-up of 12.2 +/- 4.1 months, 17 (48.6%) patients had disease progression including eight (22.9%) deaths. Patients with high CXCR1 expression, compared to those with low CXCR1 expression, had a significantly shorter 12-month progression-free survival (35.4% vs 77.9%, p=0.01) and an insignificant impact on 12-month overall survival. The CXCR1 expression scores significantly differed between patients with progressive and nonprogressive disease (20.1 vs 15.1, p=0.01) and patients with high CXCR1 expression had a reduced benefit from tyrosine kinase inhibitors. The multivariate Cox regression analysis showed CXCR1 expression as a significant predictor of progression-free survival. Conclusion: High intra-tumoral CXCR1 expression before tyrosine kinase inhibitors can be an independent prognostic factor for progression-free survival and predictor of reduced benefit in patients with metastatic clear-cell renal cell carcinoma.