Interestingly, hyperactive Hh signaling is defined as indispensable for the development of various tumors including PDAC [41–44], and YAP1 is identified as a major effector that can be upregulated and activated by Hh pathway in a subset of medulloblastomas, hepatic stellate cells and human and mouse pancreatic cancer cells [8, 45, 46]. Here, YAP1 is linked to medulloblastoma.