YAP1 and breast cancer: YAP-1 protein is overexpressed in various cancers, including colorectal cancer, gastric cancer, hepatocellular carcinoma, breast cancer, hedgehog-associated medulloblastoma, esophageal and oral squamous cell carcinoma (SCC), leukemia and other solid tumors (7, 8, 12–35), and has been referred to as an oncogene.