Nine STAT3-regulated genes (VEGFA, VIM, VVND1, ITGB6, BIRC5, MUC1, CDH1, ICAM1, and FOS) were identified as potential biomarkers to distinguish tumor from normal renal tissue by ROC analyses, with AUC values > 0.9 in at least one RCC subtype. This evidence concerns the gene FOS and renal cell carcinoma.