RRM2 and neoplasm: Subgroup analysis by different clinical features demonstrated that high RRM2 expression was significantly associated with poor prognosis in LUAD cases more than 65 years old (p = 2.287e-04), clinical stage I/II (p = 0.023), M0 (p = 0.001), N0 (p = 0.031), with tumor (p = 5.617e-04), smoker (p = 0.031), and T1/T2 (p = 0.023), as shown in Figure 3B–3H.