MAPK1 and thyroid gland undifferentiated (anaplastic) carcinoma: The 8505c cell line originates from a patient with undifferentiated highly aggressive anaplastic thyroid cancer harboring mutant p53 [28] and a BRAF V600E mutation, resulting in constitutively active MEK-ERK kinase signaling with consequent uncontrolled cell proliferation and tumorigenesis [29].