To summarize the genetic findings, we identified several different mutations segregating in the KCCMR population that are predicted to negatively affect function of two of the four MMR genes that cause Lynch syndrome in humans, MLH1 and MSH6. The other KCCMR macaques that developed CRC may also carry mutations affecting one or more of the four MMR genes. This evidence concerns the gene MSH6 and colorectal carcinoma.