Increased expression of interleukin-8 is an independent indicator of poor prognosis in clear-cell renal cell carcinoma

On the basis of aberrant interleukin-8 (IL-8) expression, a crucial angiogenesis factor and potential therapeutic target, in clear-cell renal cell carcinoma (ccRCC), this study aims to assess the prognostic significance of IL-8 in ccRCC. This retrospective study enrolled 271 patients who underwent nephrectomy for ccRCC in a single institution. The associations of IL-8 expression with clinical and pathological features were assessed using chi-squared tests. The impact on cancer-specific survival (CSS) and relapse-free survival (RFS) was analyzed using univariable and multivariable Cox regression models. The area under the receiver operating characteristic (ROC) curve (AUC) was used as an index of prognostic performance. Intratumoral IL-8 was found to be significantly elevated in ccRCC tissues compared with peritumor tissue and be predominately localized in the cytoplasm. Moreover, high IL-8 expression was positively correlated with Fuhrman grade (P < 0.001). Multivariate Cox regression analysis identified IL-8 as an independent adverse prognostic factor of CSS (P < 0.001) and RFS (P < 0.001), which could be incorporated into the traditional TNM staging system to improve the prognostic value for CSS and RFS in ccRCC patients. The predictive accuracy of traditional TNM stage model was significantly improved when IL-8 expression was added. Increased expression of IL-8 is a potential independent adverse prognostic biomarker for CSS and RFS in patients with ccRCC after nephrectomy.