DPP9 and renal cell carcinoma: Third, it integrates translational insights rarely synthesized in prior work: mapping natural compounds (icariin II and artesunate), repurposed drugs (sorafenib and melatonin), and novel modulators to disease stages (e.g., Lip-1 for fibrosis and salinomycin for RCC stem cells); highlighting strategies to reverse ferroptosis-related drug resistance (targeting DPP9 in RCC); and identifying ferroptosis-related genes (ACSL4 and PDIA4) as prognostic biomarkers.