Genetics vs. Epigenetics and Their Impact on Cancer

April 29, 2022

epigenetics

It might surprise you to know that the majority of cancers are not genetically inherited. However, certain types of cancers have a genetic component. Many other cancers are affected by epigenetics. What’s the difference between genetics and epigenetics?  short answer is you don’t have control over genetics but you do have some control over epigenetics.

Genetics vs. Epigenetics: What’s the Difference?

Genetics is the way DNA sequences are passed down from generation to generation. You inherited your DNA from your parents. Genes within that DNA control how the body works. Epigenetics is the way these passed-down genes are used.

Epigenetics is the term for the processes in which cells designate certain genes for use and others for storage. For instance, from one cell, the human embryo must develop all the cells that eventually make up a person — nerve cells, blood cells, muscle cells, liver cells and so on. It is epigenetic processes that determine which genes are used by the cell and which are not. This also affects cells’ production of proteins.

Genetic Risk Factors for Cancer

Genetics play a role in approximately 5% to 10% of cancers. It is a hereditary mutation in a gene, passed down through the generations, that increases the risk of cancer for affected individuals. If there is a history of cancer in your family, you cannot prevent it. However, undergoing regular cancer screening allows doctors to detect disease in its earliest stages — where treatment may provide a better outcome.

Researchers discovered the biological basis of cancer when defective genes were linked to the disease. Gene mutations (or changes) may increase the risk of developing cancer. Such mutations in a specific gene’s DNA sequence may lead to the uncontrolled cell division found in cancer.

A BRCA-1 gene mutation increases the risk of breast and other cancers. As the Centers for Disease Control and Prevention explained, epigenetic changes — such as an increase in DNA methylation — can result in decreased BRCA-1 gene expression. This increases breast and other cancer risks. Some patients may decide to undergo prophylactic mastectomies or ovariectomies to significantly reduce these hereditary risks.

Changes in Epigenetics

Changes in epigenetics affect gene expression and methylation adds chemical groups to DNA. The chemical group is added to particular places on DNA. There, it blocks proteins that attach to DNA to read the gene. Demethylation is the process of removing the chemical group. Think of methylation of turning genes on and demethylation of turning them off.

Sometimes, errors occur in the epigenetic process. For example, the wrong gene is modified or a chemical group is not added to a specific gene. When that happens, abnormal gene activity — or inactivity — results. Along with genetic issues, these epigenetic errors may lead to cancer.

Impact on Cancer Development

Your parents’ lifestyle and exposures, as well as your own, creates tags on your DNA which also refers to epigenetics. Let’s use identical twins as an example. Keep in mind that identical twins are clones. They have the same DNA. You probably know identical twins or may be one yourself. While identical twins are similar in many ways, their health may differ significantly as they age. That is due to epigenetic exposure factors.

The identical twins are not living the same lives. One may have substantially more exposure to environmental toxins, for example. They consume different foods, have different levels of sun exposure, and one may smoke or drink more alcohol than the other. Although their genes are identical, the identical twin with the less healthy lifestyle is at greater risk of developing cancer, heart disease and other illnesses affected by epigenetic tags. Smoking cigarettes affects DNA methylation patterns across several organ systems.

Puberty and pregnancy are times that increase the likelihood of epigenetic changes. A pregnant woman who does not eat a healthy diet may cause epigenetic changes in her offspring. Some of these changes can last a long time, affecting the child’s odds of contracting certain diseases. Overall, a healthy lifestyle has a good influence on epigenetic tags — even though it cannot change DNA.

The Future of Cancer and Epigenetics

Today, cancer is detected primarily through imaging tests or biopsy samples. These tests can only detect abnormal growths already present in the body. Epigenetic testing promises to improve current methods with more specificity and sensitivity.

Methylation-specific PCR tests can identify abnormal methylation patterns in DNA. This non-invasive test can detect cancer-specific patterns via abnormal methylation. Epigenetic-related proteins can also indicate cancer biomarkers.

Epigenetics may also lead to new and effective cancer treatments. Traditional cancer therapies, such as chemo or radiation, kill normal cells along with cancer cells. New epigenetic drugs may reprogram cancer cells instead. They may also be used in combination with other therapies to combat cancers. The future of epigenetics in cancer treatment is promising.

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Jane Meggitt’s work has appeared in dozens of publications including USA Today, Zack’s, Financial Advisor, nj.com, The Houston Chronicle and The Nest. She is a graduate of New York University.

Sources

National Cancer Insitute – The Genetics of Cancer

British Society for Cell Biology (BSCB) – Epigenetics: It’s not just genes that make us

Dana-Farber Cancer Institute – Epigenetics: How It Works And What It Means for Cancer Research

Centers for Disease Control and Prevention (CDC) – What is Epigenetics?

MedlinePlus – What is epigenetics?

The Center for Ecogenetics and Environmental Health – Genetics and Epigenetics