Characterization of thyroid cell lines. Nthy-ori3-1 cells are normal, immortalized thyroid cells expressing wild-type BRAF. BCPAP cells are papillary thyroid cancer cells and are heterozygous for the BRAFV600E mutation. Results of an XTT cell proliferation assay demonstrate percent of surviving cells after treatment with various concentrations of PLX4032. An IC50 of 10 μM PLX4032 was established for BCPAP cells and an IC50 of 20 μM PLX4032 was established for Nthy-ori3-1 cells.