PTGS2 and osteosarcoma: Conversely, inhibition of PGE2 synthesis using the COX-2 inhibitor celecoxib has been found to attenuate β-catenin stability, nuclear translocation and TCF luciferase activity in colorectal cancer [34,35], non-small cell lung cancer [36], and osteosarcoma [45], with concomitant lower expression of cyclin D1 and cell survival.