RRM2 and lung adenocarcinoma: Interestingly, the results of forest plot showed that genes such as ANLN (HR = 1.67; 95% CI: 1.1–2.53; P=0.0143), EXO1 (HR = 2.68; 95% CI: 1.76–4.07; P < 0.0001), KIAA0101 (HR = 2.41; 95% CI: 1.59–3.64; P < 0.0001), RRM2 (HR = 1.63; 95% CI: 1.09–2.42; P=0.0151), TOP2A (HR = 1.88; 95% CI: 1.25–2.32; P=0.002), and UBE2T (HR = 3.48; 95% CI: 2.16–5.61; P < 0.0001) demonstrated significantly prognostic effect in early disease, especially in pathologic stage-I lung adenocarcinoma patients.