Gain- and loss-of-function experments revealed that circCYP24A1 knockdown reduced the level of CCL5 (Fig. 4e), while circCYP24A1 overexpression promoted the level of CCL5, as shown by ELISAs in ESCC cell culture supernatants (Fig. 4f). Here, CCL5 is linked to esophageal squamous cell carcinoma.