IDH2 and non-small cell lung carcinoma: In the training set, the median level of IDH2 in the serum from patients with NSCLC was 12.50 ±8.16 ng·mL−1, which was significantly higher than that of the healthy controls (6.57 ± 5.10 ng·mL−1; Fig. 2A; P < 0.0001, Mann–Whitney U‐test).