tumour suppressor genes - of a chromosome occurs at a...

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tumour suppressor genes Tumour suppressor genes act normally to prevent cells dividing. If they are inactivated by mutation then cell division may be triggered. It is always necessary to inactivate both copies of a tumour suppressor gene. Sometimes one copy is lost through an inherited mutation. In this case every cell in the body will have only one active copy of the gene. It will not be an infrequent event that the second copy be removed because of a second somatic mutation event (remember for instance that loss
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Unformatted text preview: of a chromosome occurs at a frequency of 1 in 100 cell divisions). Patients will show multiple tumours caused by many such second events. There are many examples of inherited genes of this type such as retinoblastoma and the breast cancer genes BRCA1 andBRCA2 . The concept of the first (rare) event which must be followed by a second (much more frequent) event to initiate a cancer was first put forward by Knudsen in 1972....
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This note was uploaded on 11/22/2011 for the course CHEMISTRY CHM1025 taught by Professor Laurachoudry during the Fall '10 term at Broward College.

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