SMAD4 and esophageal squamous cell carcinoma: EAC exhibits frequent genomic amplifications of VEGFA, ERBB2, GATA4, GATA6, and CCNE1 as well as deletions of SMAD4, while ESCC generally presents amplifications of CCND1, SOX2, TERT, FGFR1, MDM2, NKX2-1, and/or TP63 as well as deletions of RB1 [4].