Fig. 2. Pre-existence of diverse ALK-TKI tolerant subpopulations.

a Representative images of crystal violet stained whole plates and microscopic images of colonies (at ×10 magnification) following 10 days of culture in DMSO or 0.5 μM lorlatinib. b Illustration of the size cut-off criteria used for quantification of limiting dilution experiments. The scale bars in a and b represent 100 μm. c Fitting of limiting dilution assay data and d quantification of the frequency of resistance-initiating cells. e Schemata of the clone-tracing experiment. f Spearman’s pairwise correlation analysis of positively selected barcodes, which have reached frequency, exceeding the highest barcode frequency in the baseline aliquot sample, between samples indicated in X and Y axes. Numbers indicate biological replicates (separate dishes). g Hierarchical clustering analysis of the positively selected barcodes shown in f. Columns indicate individual biological replicates. Rows indicate individual barcodes.