Intriguingly, we did not find frequent APC mutation in these canine samples, unlike human CRC [16], although we noted recurrent downregulation of APC. We do not know if this is related to the local genomic environment of APC. While canine APC locates at the chromosome end (near heterochromatin), human APC lies in the middle of chromosome 5 (euchromatin). Here, APC is linked to colorectal carcinoma.