Table 1 Univariate and multivariate Cox regression analyses of the 21-gene signature and OS in the training set (early-stage LUAD)

GSE30219

 Age

 > 65/ ≤ 65

23/59

1.765

0.946–3.295

7.42E−02

2.36

1.179–4.724

1.53E−02

 Gender

Male/female

64/18

0.532–2.478

7.24E−01

 T stage

T2/T1

12/69

1.019–4.107

4.40E−02

0.352–1.94

9.63E−01

 Risk score

High/low

34/48

2.287–8.114

6.16E−06

2.498–10.058

5.75E−06

GSE31210

 Age

 > 65/ ≤ 65

47/157

1.349–5.724

5.59E−03

1.445–6.964

4.01E−03

 Gender

Male/female

95/109

0.818–3.476

1.57E−01

0.347–3.078

9.54E−01

 Stage

II/I

42/462

2.092–8.828

7.21E−05

1.152–5.186

1.99E−02

 Smoking

Yes/no

99/105

0.918–3.966

8.35E−02

0.565–5.271

3.38E−01

 ALK fusion

 ± 

7/197

0.144–7.777

9.56E−01

 EGFR mutation

 ± 

116/88

0.222–0.956

3.76E−02

0.512–5.375

3.99E−01

 KRAS mutation

 ± 

19/185

0.3–3.282

9.89E−01

 Triple negative

Yes/no

62/142

0.212–0.894

2.34E−02

0.174–1.698

2.94E−01

 MYC copy

High/low

16/187

0.183–3.22

0.716942752

 Risk score

High/low

81/123

4.151–34.193

4.10E−06

2.864–27.14

1.48E−04

GSE50081

 Age

 > 65/ ≤ 65

87/40

0.774–2.735

2.44E−01

 Gender

Male/female

65/62

0.807–2.463

2.28E−01

 Stage

II/I

35/92

1.383–4.316

2.10E−03

1.068–3.399

2.90E−02

 T stage

T2/T1

82/30

1.214–4.883

1.22E−02

0.785–3.365

1.91E−01

 Smoking

Yes/no

92/23

0.75–3.776

2.07E−01

 Risk score

High/low

72/55

1.897–6.953

9.95E−05

1.373–5.455

4.24E−03

Combined data set

 Age

 > 65/ ≤ 65

157/256

1.621–3.304

3.82E−06

1.686–3.456

1.49E−06

 Gender

Male/female

224/189

1.081–2.291

1.80E−02

1.084–2.307

1.73E−02

 Stage

II/I

90/323

1.934–4.026

4.08E−08

1.42–3.004

1.49E−04

 Risk score

High/low

270/143

1.981–5.016

1.26E−06

1.863–4.846

6.44E−06