I. Determine the maximum-tolerated dose (MTD) of GSK1120212 (trametinib) combined with standard chemoradiation in unresectable non-small cell lung cancer (NSCLC) and safety as measured by the rate of grade 3 or worse non-hematological toxicities occurring prior to the beginning of consolidation therapy (including all toxicities attributed to chemoradiation occurring within 10 weeks of the start of radiation therapy).