Genetic changes marking the sequence from adenoma to carcinoma
in colon cancer
Changing of oncogenes and tumor suppressor genes
Migeod, H.F. and Scheller, A.
Fachklinik “Leonardis”, Albstraße 9, D-70806 Kornwestheim, Germany
Endoscopy with individually multiple occurring adenomas and the coincidence of adenomas and colorectal carcinomas have led to a theory of a genetic determined cause. Defined genetic changes are found in about 30 per cent in colorectal carcinomas. Consequently, so-called risk-patients should be identified and sophistically investigated. Also, a consequent endoscopy after polypectomy and resection of carcinoma is essential.
A genetically based disposition to develop a carcinoma is known for the following diseases of polyposis: the Gardner-syndrome, the familiary adomatosis and the cancer-family-syndrome (transmitted forms). On the other hand, we know the so-called forms by chance, in which also molecular genetic changes are noticed. Two molecular mechanisms are the cause of cancer because of genetic changes: Either the activation of so-called oncogenes or the inactivation of so-called tumor-suppressor genes/anti-oncogenes. Proto-oncogenes are coding for the key structures of cell multiplication (growth factors, etc.). Through point mutation, translocation, deletion and amplification an irreversible activation of these genes can occur which thus are defined as oncogenes. The loss of genes and gene sequences can also induce carcinogenesis. This mechanism is the main cause for the colorectal carcinoma and for other malignant tumors. Although many details are still not known, it is known that in 30 per cent of early adenomas (class I/II) we find defined DNS-changes. The arising of metastases also seems to be connected with proved genetic deletions.
| LOCATION |
DATE |
TIME |
| Lecture Hall II |
Tuesday, April 7 |
05:00 pm |