IDH2 and non-small cell lung carcinoma: In the test set, the median level of IDH2 in the serum from patients with NSCLC was 12.84 ± 7.42 ng·mL−1, which was also significantly higher than that of the healthy controls (4.97 ± 3.90 ng·mL−1; Fig. 2B; P < 0.0001, Mann–Whitney U‐test).