These conflicting reports were then reconciled by a large retrospective consortium analysis on 1,022 tumor samples which showed that, in the KRAS wild-type subpopulation, only PIK3CA exon 20 mutations may be predictive of lack response to cetuximab (RR of 0 % in mutant vs 36.8 % in wild-type cases) [20]. This evidence concerns the gene KRAS and neoplasm.