DHX9 and renal cell carcinoma: Since circRNAs are derived from pre-mRNAs and circRNAs can be regulated by RNA-binding proteins post- transcriptionally, we determined the expression of circPRRC2A in RCC cell lines after individually depleting all three known human circRNA-binding proteins (QKI, ADAR1 and DHX9) that have been shown to regulate circRNA biogenesis 25-28.