PARP1 and osteosarcoma: The factors significantly associated with both OS and RFS of osteosarcoma patients in univariate analysis were tumor size (OS; P = 0.011, RFS; P = 0.024), tumor stage (OS; P = 0.008, RFS; P = 0.014), distant metastasis at diagnosis (OS; P = 0.005, RFS; P = 0.016), histologic grade (OS; P = 0.024, RFS; P = 0.017), and the expression of PARP1 (OS; P = 0.047, RFS; P = 0.039), γH2AX (OS; P = 0.004, RFS; P = 0.003), and BRCA2 (OS; P = 0.005, RFS; P = 0.017).