CCND1 and esophageal squamous cell carcinoma: ATRA is known to induce differentiation and inhibit stemness in multiple cell types,[16] and involved in the downregulation of some β‐TrCP substrate proteins, including TWIST, MYC, CCND1, and CTNNB1.[17] Thus, we speculated that ATRA may selectively target ESCC cancer cells and suppress their TIC properties.