TREM2 and nonpapillary renal cell carcinoma: A single-cell study about clear cell renal carcinoma(ccRCC) found that APOE was significantly enriched in tumors from patients who recurred following surgery, identified TREM2-APOE-C1Q-positive macrophages infiltration as a potential prognostic biomarker for ccRCC recurrence, as well as a potential therapeutic target (40).