HERG1 overexpression induced downregulation of p21 and upregulation of cyclin D1 in ESCC cells, whereas HERG1 knockdown induced upregulation of p21 and downregulation of cyclin D1 (Fig. 2f and g), suggesting that HERG1 is involved in ESCC cell cycle progression. Here, CCND1 is linked to esophageal squamous cell carcinoma.