Fig. 3.

Constrained tumorigenic pathways among multicentric lesions. a A summary of the most prominent driver mutation identified in each primary tumor of MSLC. b EGFR or KRAS was knocked out using CRISPR-Cas9 system in lung cancer cell lines and replaced with HER2, c-MET, ARAF, BRAF, or MEK mutants. c EGFR was knocked out using CRISPR-Cas9 system in PC9 cells and replaced with HER2^YMVA. AKT and ERK phosphorylation were measured by western blot analysis. d Cells were treated with a serial dilution of indicated inhibitors for a week and stained with crystal violet. Scale bar, 5 mm. The corresponding cell lysates were analyzed by immunoblotting. e KRAS was knocked out using CRISPR-Cas9 system in NCI-H1944 cells and replaced with BRAF^D594G, c-MET^ΔE14, ARAF^S214C, or MEK1^{E102-I103 del}. ERK phosphorylation was measured by western blot analysis. Indicated cells were treated with a serial dilution of trametinib for a week and stained with crystal violet. Scale bar, 5 mm. The corresponding cell lysates were analyzed by immunoblotting