Tumour suppressor genes and colorectal carcinoma

Several tumour suppressor genes have been identified as being involved in tumour initiation and progression:

• inactivation of the DCC gene:
  • DCC stands for Deleted in Colon Cancer
  • on chromosome 18q
  • DCC is a membrane-bound protein that shares sequence homology with neural adhesion molecules (N-CAM)
  • DCC is xpressed in the axons of peripheral and central neurons and in differentiated cells of the intestine
  • DCC mutations have only been found in sporadic colorectal cancers
    
    
• APC:
  • the Adenomatous Polyposis Colon gene
  • mutations of the APC tumour suppressor gene are unique to colorectal carcinomas
    
    
• mutHLS homology genes:
  • these proteins are involved in mismatch repair of DNA
  • dysfunction results in the hereditary non-polyposis colorectal cancer