AKT3 and nonpapillary renal cell carcinoma: Furthermore, although several circRNAs, including circHIAT1 21, circ-AKT3 22, and cRAPGEF5 23, have been shown to play important roles in the initiation and progression of ccRCC 18, systematic investigation of circRNAs implicated in ccRCC development, as well as their underlying molecular mechanisms, are still lacking.