Consistent with our observations in HepG2, circCDYL is much higher expressed than the mRNAs of its interacting RBPs, IGF2BP1 (> 180×) and IGF2BP2 (> 5×), in both bladder cancer cell lines, supporting circCDYL’s potential to act as a sponge (Additional file 8: Fig. S6L). This evidence concerns the gene IGF2BP2 and urinary bladder carcinoma.