A significantly lower proportion of patients with MMR-proficient tumors with mutant BRAF ( hazard ratio = 1.43 ; 95 % confidence interval : 1.11-1 .85 ; Padjusted = .0065 ) or mutant KRAS ( hazard ratio = 1.48 ; 95 % confidence interval : 1.27-1 .74 ; Padjusted < .0001 ) survived disease-free for 5 years compared with patients whose MMR-proficient tumors lacked mutations in either gene .