High mucin-7 expression is an independent predictor of adverse clinical outcomes in patients with clear-cell renal cell carcinoma.

Mucin-7 is a member of the secreted mucins family. Mucins might play a crucial role during tumor development and its aberrant expression was observed in several types of tumor. Our study aims to evaluate the prognostic significance of Mucin-7 expression in postoperative clear-cell renal cell carcinoma (ccRCC) patients. In this retrospective study, we enrolled 392 patients with ccRCC undergoing nephrectomy between 2008 and 2009 in a single center. The median follow-up was 73 months (range 39-74 months). Mucin-7 expression was evaluated by immunohistochemistry protocol on ccRCC specimens. Kaplan-Meier survival analysis was conducted to compare survival curves. Univariate and multivariate Cox regression models were applied to assess the impact of prognostic factors in overall survival (OS) and recurrence-free survival (RFS). A nomogram was then constructed based on the independent prognosticators identified on multivariate analysis. The results displayed that Mucin-7 expression was significantly associated with tumor size (p = 0.034), pT stage (p = 0.004), TNM stage (p = 0.008), and necrosis (p = 0.043). Patients with high Mucin-7 expression had significant worse outcomes in both OS (p < 0.001) and RFS (p < 0.001) compared to those with low Mucin-7 expression. MUC7 expression was considered as an independent predictive factor for OS (HR 2.286; 95 %CI 1.167-4.475; p = 0.016) and RFS (HR 2.055; 95 %CI 1.086-3.887; p = 0.027). A nomogram integrating Mucin-7 expression and other independent prognosticators was constructed. In summary, the high Mucin-7 expression is a potential prognosticator of adverse clinical outcome in ccRCC patients after surgery.