Granulocyte macrophage colony-stimulating factor predicts postoperative recurrence of clear-cell renal cell carcinoma

Granulocyte macrophage colony-stimulating factor (GM-CSF) is currently widely used as an adjuvant in cancer immunotherapy. However, recent studies have shown that GM-CSF can impair anti-tumor immune responses. Thus the role of GM-CSF in clear-cell renal cell carcinoma (ccRCC) remains unraveled. Our present study aims to investigate the prognostic significance of intratumoral GM-CSF in patients with clinically localized ccRCC.

A high intratumoral GM-CSF expression was significantly associated with lymph node metastases (P = 0.009), high TNM stage (P = 0.031), high Fuhrman grade (P < 0.001), presence of tumor necrosis (P = 0.005), and high Leibovich scores (P < 0.001). In addition, the prognostic significance of intratumoral GM-CSF expression was restricted to patients with Leibovich intermediate/high-risk (P = 0.001). Furthermore, a high intratumoral GM-CSF expression was demonstrated as an independent prognostic factor of reduced RFS (P = 0.018). Incorporation of the intratumoral GM-CSF expression into a prognostic model including TNM stage, Fuhrman grade, tumor necrosis and lymphovascular invasion generated a nomogram, which predicted accurately 3- and 5-year survival for ccRCC patients.

This study comprised 233 clinically localized (T1-3N0-1M0) ccRCC patients undergoing nephrectomy in 2008 at a single centre. Intratumoral GM-CSF expression was assessed by immunohistochemical staining and its associations with clinicopathologic features and recurrence-free survival (RFS) were evaluated.

The intratumoral GM-CSF expression, as a potentially independent prognostic biomarker for recurrence, might improve conventional clinical and pathologic analysis to refine outcome prediction for clinically localized ccRCC patients after surgery.