Table 3. Multivariate Cox model of training, testing and validation cohorts.

Variable	Hazard Ratio (95% CI)	P Value
Training cohort
High-risk six-gene signature	3.14 (1.14–8.67)	0.027
Male	1.74 (0.39–7.82)	0.47
Older age	1.02 (0.97–1.07)	0.43
Adenocarcinoma	2.65 (0.95–7.43)	0.06
Tumor stage III	4.66 (1.51–14.39)	0.01
Testing cohort
High-risk six-gene signature	5.42 (1.56–18.84)	0.008
Male	7.23 (0.81–64.97)	0.08
Older age	1.01 (0.94–1.08)	0.83
Adenocarcinoma	0.97 (0.35–2.70)	0.95
Tumor stage III	11.18 (3.43–36.40)	< .0001
Validation cohort
High-risk six-gene signature	1.50 (1.25–1.80)	< .0001
Adenocarcinoma	0.65 (0.54–0.78)	< .0001
Male	1.43 (1.17–1.74)	0.0005