Epigenetics

Epigenetics and Cancer

Several genetic mutations have been implicated in the initiation of cancer but little has been explained about the role of mutation in cancer progression.

Keeping this in mind, scientists such as Feinberg suggest the possible involvement of epigenetics in activating oncogenes, thereby initiating tumors and also of their role in cancer progression or, metastasis.

DNA methylation and histone modifications cause epigenetic changes in potential cancer cells. The role of DNA methylation in human cancer was first confirmed in 1983, and since then it has been understood to play a role in many other health conditions.

There are a group of genes, known as the tumor suppressor genes (TSG) that act as surveillance bodies in the cells. When certain regions, particularly the CpG islands of the TSGs are hypermethylated, they get switched off. This in turn leads to instability within the genome leading to the activation of cancer -causing oncogenes.

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The role of histones in cancer has also been ascertained. During the various modifications of the histone N-terminal tails, to maintain chromatin stability, a loss of expression of a TSG could initiate cancer formation.

A range of compounds have been discovered to be epigenetic carcinogens that increase tumor incidence. Examples are arsenite, hexa chlorobenzene, diethylstilbestrol, and nickel compounds.