Tumours with increased levels of both AREG and EREG ligands and a KRAS WT benefited the most from anti-EGFR therapies these findings shows strong predictive value as KRAS and NRAS have strong negative predictive value [47, 48, 56, 112, 113], with a recent publication reporting that patients with KRAS mutant adenocarcinoma of the lung with induced epiregulin expression was associated with an aggressive phenotype [117]. The gene discussed is KRAS; the disease is lung adenocarcinoma.