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Epigenetics and Cancer Introduction: Cancer is beyond mutations. By definition, epigenetics is the

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Epigenetics and Cancer
Introduction:
Cancer is beyond mutations. By definition, epigenetics is the change in gene translation that is caused by alterations not directly due to genetic mutations in the DNA sequence. The 2 main mechanisms are DNA methylation and covalent modification of histones. By methylation, certain molecular tags (methyl groups) bind to a specific sequence of a gene, that results in its disability hence incapable of being translated into its appropriate protein product. These changes affect the cell’s functions leaving its DNA unchanged. Epi is derived from Latin meaning above; hence an epigenetic configuration overlies our genetic predispositions.

DNA methylation and Cancer:
DNA methylation primarily occurs within …show more content…

Some of the factors affecting DNA methylation without DNA change are: Aging: Aging results in the hypomethylation of the genome, while CpG islands are hypermethylated often. Diet: Folate and methionine pathways are sources of methyl groups for DNA and histones. Methyl groups can’t be acquired directly without these cycles. Hence, a diet low in folate and methionine ultimately leads to an alteration in DNA methylation. Environment: Many chemicals in nature can induce epigenetic changes. These include arsenic and cadmium. Arsenic for example leads to the hypomethylation of ras gene which codes for the production of ras proteins that help each cell to grow and divide in appropriate times. Cadmium in turn leads to global hypomethylation by inactivating DNMTs.

In discussion of methylation and cancer is the concept of allelic imprinting. Bannister (n.d.), discusses that DNA methylation is an epigenetic factor for allelic imprinting. The concept of allelic imprinting is when only one of the genes is expressed depending on the parental origin. That is due to methylation, a gene “remembers” what allele to express, either the paternal or the maternal allele. Hence, loss of imprinting due to a defect in methylation leads to cancer. To make things clearer, the example of IGF2 (insulin like growth factor 2) is an imprinted gene expressed only by paternal alleles. If no methylation exists

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