Frequently mutated genes in ESCC include TP53, NOTCH1, NFE2L2, CDKN2A, PIK3CA, RB1, FAM135, ADAM29, MLL2, FBXW7, AJUBA, CREEBP, PTCH1, ZNF750, PTEN, FAT1, EP300, FAT2, KDM6A, CREBBP, BAP1, NOTCH3, TGFBR2, CUL3, DCDC1, NAV3, TENM3, TET2, RIPK4, PBRM1 and USP8 [44,52,53,54,55,56,57,58] (Figure 1, including full gene names). This evidence concerns the gene PIK3CA and esophageal squamous cell carcinoma.