 Eligible subjects will be randomized to receive trametinib at the recommended Phase II dose of 2 mg every day as one 2 mg tablet or four 0.5 mg tablets on Day 1. From Day 2 until disease progression or withdrawal from the study treatment, all subjects will receive one tablet of 2 mg trametinib . Disease assessment will be performed every 8 week. Translational research is also planned to evaluate the potential blood or tumor tissue-derived biomarkers for biological activity, and sensitivity or resistance to treatment with trametinib . 