Staub et al. [13] assumed that deletion or epigenetic silencing of the chromosomal region 5 q23.2 where CDO1 is located is a frequent mechanism contributing to colorectal tumorigenesis; adenomatous polyposis coli (APC) and mutated in colorectal cancer (MCC) are located in the neighborhood of 5 q23 [12]. This evidence concerns the gene APC and Merkel cell skin cancer.