COL2A1 and chondrosarcoma: To further investigate the potential function of Trp53 and Rb1 in chondrosarcoma, we generated the mouse conditional knockout lines in which Trp53 or/and Rb1 were deleted in chondrocyte lineage by crossing Trp53f/f, Rb1f/f and Trp53f/f/Rb1f/f floxed mice with a transgenic Cre line driven by a Col2a1 promoter (henceforth referred to as Col2-Cre;Trp53f/f, Col2-Cre;Rb1f/f, and Col2-Cre;Trp53f/f/Rb1f/f mice).