A good example of this is colorectal adenocarcinoma, where the cells of origin, i.e. the glandular epithelium of the large bowel, express standard form of CD44 (CD44s), but not variant ones (CD44v), while highly dysplastic colorectal adenomas, primary and metastatic colorectal cancers express a large variety of different-length CD44 isoforms, both on mRNA and protein levels [14,31,44,77-79]. This evidence concerns the gene CD44 and metastatic colorectal cancer.