The MMR system has been suggested to influence prostate carcinogenesis e.g. through an increased risk of prostate cancer linked to single nucleotide polymorphisms in MLH1 and MSH3, and a role for complex structural rearrangements in MSH2 and MSH6 as a mechanism underlying the hypermutation in aggressive prostate cancer [14–20]. The gene discussed is MSH3; the disease is prostate cancer.