KRAS and esophageal squamous cell carcinoma: KRAS WT amplifications were confirmed in esophageal adenocarcinoma (∼15.5%), adenocarcinoma of the gastroesophageal junction (∼10.2%), stomach adenocarcinoma (∼4.6%), and esophageal SCC (∼4%; Fig. 2D; Supplementary Table S3).