An 81-year-old Hispanic man was referred to our gastrointestinal medical oncology clinic for recurrent colon adenocarcinoma…. FoundationOne (Foundation Medicine, Inc., Cambridge, MA) was performed on his archival tumor tissue. Molecular profiling identified a hypermutated tumor profile encompassing 100 total genomic alterations with a tumor mutational burden (TMB) of 122 mutations per megabase (Mb); alterations in POLEV411L and RAF1R256S were also identified...He received 3 cycles of pembrolizumab intravenously at 200 mg every 3 weeks and experienced an improvement in his performance status and resolution of fatigue... the patient had completed 8 cycles of pembrolizumab with ongoing clinical benefits and no associated toxicity.