As an effort to model acquired resistance of ERBB2-amplified GE adenocarcinomas to ERBB2 inhibition, we generated lapatinib-resistant subclones from an initially lapatinib-sensitive ERBB2-amplified esophageal adenocarcinoma cell line by prolonged exposure to the inhibitor. This evidence concerns the gene ERBB2 and esophageal adenocarcinoma.