ATR and adenocarcinoma: The only biomarker driven therapy in clinical practice to date is trastuzumab, a humanized monoclonal antibody against HER2 [21] which is amplified in 15–25% of adenocarcinomas of the esophagus; future treatment strategies should increasingly incorporate drugs that exploit aberrations in specific signaling pathways (in this case, ATR inhibition in a p53 mutated tumor).