PIK3CA and neoplasm: The only complex genotype that harboured significance for cetuximab benefit was CG3 (p=0.019): Patients with tumours wild-type for all PIK3CA, KRAS, BRAF reached a median survival of 32 months (95% CI 25–36), those with a PIK3CA mutation along with KRAS or BRAF mutation had a median survival of 26 months (95% CI 16–32) while patients with any single mutation in KRAS, BRAF or PIK3CA genes had a median survival of 22 months (95% CI 19–28).