Circ-ZNF609 was reported to act as a competitive miR-138-5p sponge and suppress its expression, then release FOXP4 and promote the progression of RCC (Xiong et al., 2019), whereas cRAPGEF5, derived from the RAPGEF5 gene, was downregulated in RCC and the sponged miR-27a-3p released, resulting in decreased expression of TXNIP and blocking the progression and migration of RCC (Chen Q. et al., 2020). Here, FOXP4 is linked to renal cell carcinoma.