CUL3 and esophageal squamous cell carcinoma: Mutations of the NFE2L2 gene are observed in 10–20% of ESCC cases; other genes of the NFE2L2 pathway are also mutated in ESCC: somatic mutations of KEAP1 (2–4% of cases), somatic mutations or deletions of CUL3 (1–5%) and deletions of ATG7 (6% of cases) [27,81].