Table 3. Multivariate analysis of clinical outcome by Cox proportional hazards model.

	Disease-free survival		Overall survival
Variables	HR (95% CI)	P -value	HR (95% CI)	P -value
TOP2B/TOP2A ratio
High (⩾1.0, N=21)	1		1
Low (<1.0, N=33)	4.17 (1.73–10.10)	0.002	3.4 (1.5–8.1)	0.005
Cytogenetics		0.035
Normal (N=16)	1
t(8;21) (N=24)	0.45 (0.17–1.15)	0.094	—	—
Others (N=14)	1.35 (0.51–3.61)	0.544	—	—

Abbreviations: CI=confidence interval; HR=hazard ratio.

Gene markers and clinical factors, for example, RRM2, TOP2B, TOP2B/RRM2, TOP2B/TOP2A, age, cytogenetics and HSCT, which displayed P-value <0.2 in univariate analysis, were considered in this analysis. Exceptively, we included TOP2A in the variables even though a predictive significance of this gene was not satisfied to our criteria in univariate analysis. Shown are the variables remaining only in a final model of the Cox proportional hazard model with a stepwise forward method.