KRAS and non-small cell lung carcinoma: Consequently, approval for gefitinib administration was expanded in 2011 to include “EGFR mutation-positive inoperable or recurrent non-small-cell lung cancer.” Similarly, the efficacy of cetuximab, an antibody drug for colorectal, head, and neck cancers, was found to be influenced by the presence of KRAS mutations; accordingly, the administration guideline for cetuximab was modified in 2010 and must now consider the presence or absence of KRAS mutations (6), (7).