It is now generally accepted that CRC mainly develops through two different genetic pathways, of which one is the chromosomal instability pathway characterized by the involvement of APC, p53, and k-ras genes, by 18q allelic loss, and by aneuploidy DNA content, while the other is a pathway involving microsatellite instability (MSI)3. This evidence concerns the gene TP53 and colorectal carcinoma.