We demonstrate that circ‐CUX1 interacts with EWSR1 protein to increase MAZ transactivation, which subsequently regulates the transcription of CUX1 and other genes associated with tumor progression in cis and in trans (Fig 6I), such as S100A9 (Lim et al, 2016), MUC4 (Rowson‐Hodel et al, 2017), KLF10 (Weng et al, 2017), and TXNIP (Shen et al, 2015). Here, MUC4 is linked to neoplasm.