GSK1120212 is a reversible and highly selective allosteric inhibitor of MEK1 and MEK2 activation and kinase activity currently being developed for the treatment of malignant melanoma. This is a Phase I, open-label, non-randomized, single-dose study designed to characterize the absorption, distribution, metabolism, and elimination (ADME) of a single oral dose of MEK inhibitor [14C]GSK1120212 as a solution in male subjects with solid tumor malignancies. A sufficient number of subjects will be enrolled to complete approximately four evaluable subjects. Following completion of the study, subjects may elect to continue dosing with GSK1120212 in the rollover study, MEK114375.