Molecular events in multistep carcinogenesis

소개

Molecular events in multistep carcinogenesis에 대한 대학원 리포트 입니다. (영어)

목차

I. PROCESS OF CARCINOGENESIS

II.MECHANISMS OF ONCOGENE ACTIVATION

III. CANCER GENES

IV. THEORIES OF CARCINOGENESIS

V. FACTORS INFLUENCING CANCER DEVELOPMENT

VI. CELLULAR DEFENSE MECHANISMS IN RELATION TO CANCER PREVENTION AND CARCINOGENESIS

본문내용

II.MECHANISMS OF ONCOGENE ACTIVATION
Each oncogene is closely associated with a normal DNA sequence present in the cellular genome, the proto-oncogene. At least five different mechanisms are considered for the conversion of proto-oncogenes to active oncogenes
(1) Overexpression of proto-oncogene following acquisition of a novel transcriptional promoter. The oncogene then acquires activity because their transcripts are produced at much higher levels than those of the related normal proto-oncogene.
(2) Over-expression due to amplification of the proto-oncogene or oncogene. The increased gene copies cause corresponding increases in transcript and gene product. (3) Influences on the levels of transcription and, in turn, the amount of gene product. (4) Juxtaposition of the oncogene and immunoglobulin domains, following chromosomal translocations, that appears to result in deregulation of the gene.
(5) Alteration in the structure of the oncogene protein. This is the most well documented mechanism in the case of the oncogene proteins encoded by the ras genes.
The fourth and fifth mechanisms seem to be inter-related.
A translocation can disturb the regulation of an oncogene by:
a) providing a new promoter region or some other control element that would activate the oncogene; or
b) altering the coding sequence of a gene, changing its protein product from a benign to a malignant form.
A close association between specific chromosomal translocations and certain human
neoplasms has been demonstrated

참고자료

· Robinson;s Pathologic basis of disease