IHC-positivity was associated with KRAS mutation, both in D4D6 (OR 6.5, 95% CI 2.3–18.7, p = 0.001) and SP384 (OR 2.9, 95% CI 1.1–8.1, p = 0.04), but when we adjusted for adenocarcinoma histology there was no significant association. Here, KRAS is linked to adenocarcinoma.