Major rationales for changes in adenocarcinoma histologic variants are that the invasive mucinous type shows frequent mutations in KRAS and hardly any in EGFR, whereas non-mucinous adenocarcinoma of predominant lepidic subtype is characterized by frequent mutations in EGFR and fewer in KRAS [20]. The gene discussed is KRAS; the disease is colon mucinous adenocarcinoma.