Table 1. Correlations of PRDX1 expression with clinicopathological variables of osteosarcoma in training and validation cohort.

Variables	Training Cohort				Validation Cohort
	PRDX1 Expression				PRDX1 Expression
	N	Low	High	P value	No.	Low	High	P value
Gender
Male	75	31	44	0.676	67	22	45	0.584
Female	35	13	22		23	9	14
Age (years)
< 45	57	20	37	0.275	54	19	35	0.856
> 45	53	24	29		36	12	24
Anatomical site
Femur/Tibia	89	36	53	0.843	67	21	46	0.291
Elsewhere	21	8	13		23	10	13
Tumor size (cm)
< 8	50	30	20	< 0.001	41	22	19	< 0.001
> 8	60	14	46		49	9	40
ALP level(U/L)
< 150	44	16	28	0.525	31	11	20	0.880
> 150	66	28	38		59	20	39
Pathological fracture
Absent	91	41	50	0.018	69	27	17	< 0.001
Present	19	3	16		21	4	42
Ennecking grade
2a	61	30	31	0.028	47	23	24	0.002
2b	49	14	35		43	8	35
Histologic grade
Low	65	33	32	0.006	47	24	23	0.001
High	45	11	34		44	8	36
TNM stage
I/II	62	32	30	0.005	47	25	22	< 0.001
III	48	12	36		43	6	37