YAP1 and osteoblastic osteosarcoma: Moreover, the lncRNA H19 is abnormally expressed by the Hh/Gli signalling pathway and Yap1 overexpression, suggesting that the Hh pathway is an important regulator of osteoblasts during the tumourigenesis of osteoblastic osteosarcoma via the overexpression of Yap-1 and the lncRNA H1969.