PLX4032 causes apoptosis selectively in mutated papillary thyroid cancer cells. A) Nthy-ori3-1 and BCPAP cells were plated in six-well culture dishes in the presence of 10 μM PLX4032 for 36 hours. Viable cells were counted using a trypan blue dye exclusion assay. Asterisks indicate statistically significant differences (p < .05) between control and treated samples. B) Nthy-ori 3–1 and BCPAP cells were treated with 10 μM PLX4032 for 36 hours and apoptotic and necrotic cells were visualized by immunofluorescence. Red staining is indicative of necrotic cell death as a result of cellular insult and membrane disruption and green staining marks apoptotic cells that express Annexin V on their outer membranes. (Blue: Hoechst 33342, Red: Ethidium Homodimer III, green: FITC-Annexin V).