KRAS and esophageal squamous cell carcinoma: Regarding genomic amplification, it was noted that CCDN1, FGF19, FGF3, FGF4, SOX2, PI3KA, and MAP3K13 were frequently amplified in ESCC, whereas ERBB2, KRAS, CCNE1, RARA, GATA4, and VEGFA amplifications were more common in EAC in this study, as similar to the literature.