Four potential targets (THRB, PFKB2, CMTM4, and PAPPA) were identified, but only CMTM4 expression increased with the overexpression of circCYP24A1 (Fig. 4B), indicating that CMTM4 was the target of miR-421 in RCC cells. The gene discussed is PAPPA; the disease is renal cell carcinoma.