KRAS and neoplasm: In the full cohort of patients with known KRAS mutation status (all stages included), tumor histopathology was also prognostic of OS (p < 0.001); poorly differentiated/anaplastic tumors had shorter overall survival (median OS = 21 months; HR: 2.3, 95% CI 1.4-3.9) than patients with well-differentiated tumors (median OS = 62 months) (Fig. 3b).