Herein, we present the case of a 48-year-old female who presented with abdominal pain and was subsequently diagnosed with moderately differentiated adenocarcinoma of the gallbladder (pT2bN1M0) and well-differentiated adenocarcinoma of the transverse colon (pT3N0M0), with no loss of MMR protein expression in either tumor. The gene discussed is MRC1; the disease is adenocarcinoma.