KRAS and colorectal carcinoma: The CALGB/SWOG 80405 not only demonstrated poorer prognosis associated with right sided CRC, but KRAS wild type right sided tumors had significantly worse median OS relative to left sided KRAS wild type tumors when treated with cetuximab and chemotherapy (16.7 months (95% CI 13.1-19.4) vs 36 months (95% CI 32.6-40.3) (Table 1) (26).