PEBP1 and nonpapillary renal cell carcinoma: We chose urine as the first sample for analysis based on our previous results by Gasparri et al. [31], which demonstrated the diagnostic power of urinary volatile organic compounds (VOCs) for detecting early-stage lung cancer, and Papale et al. [30], who highlighted the potential of assessing urinary RKIP and pRKIP as novel biomarkers for clear cell Renal Cell Carcinoma (ccRCC).