Epigenetics and Cancer
In the science of genetics, epigenetics is the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.
Attention has, over time, moved further from the DNA’s code and more toward the way that DNA is packaged and the proteins that interact with it. These so-called epigenetic factors can be inherited, are reversible, and hugely influential.
Every cell in the human body (except for a few) contains exactly the same DNA, but not every part of the DNA is active at the same time. A liver cell, for instance, will have different portions of DNA “switched on” to a skin cell or muscle cell.
Epigenetic mechanisms are responsible for ensuring the correct DNA information is expressed in each specific cell type.
Similarly, throughout our lives, various genes can be silenced or expressed; these fluctuating expression rates can be influenced by countless life events and behaviours such as where we live, environmental pollution, aging, and exercise.
As research into epigenetics has developed and advanced, scientists have discovered that some traits can be developed and passed from generation to generation without any changes in the gene sequence (genotype).
Epigenetics research has shown that an environmental factor such as living in a smoke-filled environment, for instance, can alter certain aspects of the way genes function (but not the base pairs themselves), which are then passed on to future generations.
Epigenetics and Cancer
Cancer has a strong genetic component and it is now believed that epigenetic factors have a deep involvement and influence over various aspects of cancer’s progression.
Cancer was the first human disease to be linked to epigenetics way back in 1983; researchers discovered that genes within colorectal cancer cells were significantly less methylated than normal tissue (methylation is a process where methyl groups are added to DNA; most often, this has the effect of repressing gene transcription – the first step of DNA replication, where DNA is copied into RNA).
It is now known that too little methylation can create instability in chromosomes and activate oncogenes; and too much methylation can initiate silencing of the genes responsible for suppressing tumours.
Because epigenetics involves reversible changes to aspects of chromatin (a complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells), an understanding of its role in various diseases could lead to innovative new treatments.
A study published in Carcinogenesis in 2009 says:
“The fact that epigenetic aberrations, unlike genetic mutations, are potentially reversible and can be restored to their normal state by epigenetic therapy makes such initiatives promising and therapeutically relevant.”
Epigenetics, as a field of study, is still very new, but much more research is definitely called for due to its wide-ranging influence in health and disease. Only time will tell how much influence epigenetics has over us and our offspring, and how much influence medical science will eventually have over it.