STAT3 and renal cell carcinoma: Lastly, Huang and colleagues discovered that clear cell RCC-derived exosomes containing circSAFB2 contribute to the polarization of M2 macrophages via the miR-620/JAK1/signal transducer and activator of transcription 3 (STAT3) axis, thereby remodeling the TME and promoting clear cell RCC metastasis [81].