EGFR and lung cancer: In addition, even though about 1/3 of lung cancers possess a mutation of KRAS, no specific inhibitor is available in the clinic so far; moreover, mutations in KRAS are mutually exclusive with EGFR mutations and are associated with resistance to chemotherapy or EGFR inhibitors (Eberhard et al., 2005), thus leaving a significant percentage of lung cancer patients with a potentially actionable mutation with few therapeutic options.