YAP1 and cancer: Aberrant activation of YAP due to mutations in upstream components, gene amplification or fusion, or other unknown mechanisms promotes tumor progression in many types of cancer including hepatocellular carcinoma, lung adenocarcinoma, gastric cancer, colon cancer, mesothelioma, schwannomas, ependymomas, cervical squamous cell carcinoma, uveal melanomas, and esophageal squamous cell carcinoma (2, 3, 14).