Figure 1

BRAF V600E IHC positive PXA cases molecularly confirmed as BRAF V600E mutant tumors: case 17 - strong granular cytoplasmic immunostaining of a characteristic pleomorphic multinucleated giant tumor cell (A), case 3 - weak granular cytoplasmic immunostaining of pleomorphic and spindle tumor cells (B), case 10 - strong granular cytoplasmic immunostaining of a cluster of isolated tumor cells (C), 400X; and case 14 - mutant BRAF V600E peak in addition to the wild-type BRAF peak, consistent with presence of BRAF V600E mutation (D).