We used two cell lines, T1860 and T1903, which we have derived from anaplastic tumors developed by [Pten, p53]thyr−/− mice, to determine the sensitivity of these murine ATCs cells to specific pathway inhibition, and compared them to the human follicular carcinoma line FTC-133 (PTEN and p53 mutant), and the human ATC lines CAL-62 (KRAS and p53 mutant) and C643 (HRAS and p53 mutant). The gene discussed is KRAS; the disease is thyroid gland follicular carcinoma.