<h4>Background</h4>For patients with aggressive thyroid cancer, including anaplastic thyroid carcinoma (ATC) and high-grade follicular cell-derived non-anaplastic thyroid carcinoma, rapid BRAF p.V600E testing is critical as targeted therapy with BRAF/MEK inhibitors significantly improves outcomes. The gene discussed is MAP2K7; the disease is thyroid gland undifferentiated (anaplastic) carcinoma.