FGF2 and esophageal squamous cell carcinoma: CDR1as and circHIPK3 were shown to promote EGFR receptor expression in colorectal cancer (CRC) and esophageal squamous cell carcinoma (ESCC) [41, 42], while circWDR77 enhanced FGF2 ligand expression in vascular smooth muscle cells [43](Fig. 2a).