Fig. 4

Tumor mutation burden (TMB) in paired primary lung and CNS lesions. TMB distribution of patients with brain metastasis (n = 18) (A, B) and leptomeningeal metastasis (n = 11) (C, D). A, C Histograms showing the TMB calculated for the paired primary and CNS lesions per patient. B, D Box plots comparing the TMB between primary lung lesion and brain metastatic tissues (B) and between primary lung lesion and CSF (D). P value was calculated by Wilcoxon test. CNS central nervous system, BM brain metastasis, LM leptomeningeal metastasis, CSF cerebrospinal fluid