ALK and lung cancer: A second major difference that distinguishes ALK-driven lung cancers from their EGFR+ counterparts is an apparently even lower genetic complexity based on a very low tumor mutational burden (TMB, mean 2.0 vs. 5.0 mutations/Mbp in the MSKCC cohort [35-37], p < 0.001, Figure 2A), a lower frequency of TP53 mutations (25% vs. 42%, p < 0.01, Figure 2B, 2C) [18, 19, 35], and few other co-mutations (Figure 2D) [19, 22].