Fig. 5. Encorafenib and dabrafenib exhibit distinct heterogeneous tumor penetration.

(A) Simulation of parent dabrafenib or encorafenib, given by intravenous bolus in mice, and their penetration from a fully perfused margin into the avascular center of a 1-mm spherical tumor. (B) Representative mass spectrometry imaging (MALDI MSI) of unlabeled dabrafenib and encorafenib and corresponding standard tissue phantoms (calibration curves shown in fig. S9). Tissues were analyzed 4 hours after injection in the subcutaneous YUMMER1.7 melanoma model. Regions highlighting dense tumor (brown) versus stroma, as guided by hematoxylin and eosin (H&E), with corresponding mean drug concentrations are shown on the left (scale bars, 1 mm). Line profiles depicting drug concentration are shown in the inset and graphed in (C).