KRAS and rectal cancer: Patients with proximal CRCs had a higher frequency of KRAS (39.1%) and BRAF (16.0%) mutations and worse prognosis (median survival 397 days) compared to patients with distal (25.6%, 4.3% and 514 days, all P < 1.0 × 10–4, respectively) and rectal cancers (33.3%, P = 1.2 × 10–2; 4.1%, P < 1.0 × 10–4 and 520 days, P < 1.0 × 10–4, respectively) (Table 1).