MMR protein immunohistochemical analysis (i.e., MLH1, PMS2, MSH2, and MSH6; Dako, Glostrup, Denmark) [15] of the right-sided colonic tumour showed an unusual pattern of large areas (almost 50% of the tumour) of dMMR characterized by the complete loss of the coupled MLH1/PMS2 coexistence with areas with retained MLH1/PMS2 immunoreactivity (Fig. 2a). The gene discussed is PMS2; the disease is colonic neoplasm.