NEDD4L and esophageal squamous cell carcinoma: Considering NEDD4L is the E3 ubiquitin ligase which has the highest confidence connect with xCT (Fig. S1 and Table S2) and xCT expression is increased in ESCC samples when compared to normal tissue (Fig. S5A) (UALCAN database: https://ualcan.path.uab.edu/index.