Genetics and their role in impacting cancer risk can be a daunting subject.
Not only is it easy to get lost in science-speak, but sometimes the subject can bring up fears in people who feel they are ‘doomed’ because a family member had cancer. But did you know that only a few cancers – between five and 10 per cent – are caused by inheriting a gene mutation? So, what’s a gene mutation? I recently found an explanation on the Canadian Cancer Society’s website, cancer.ca, that made the entire topic a little less complex.
All cancers are caused by a permanent change in, or damage to, one or more genes.
A change in a gene is called a gene mutation. A mutation in a gene changes the instructions it gives to the body and stops it from working properly, which can upset normal development or cause a medical condition. Gene mutations have varying effects on health but can cause cells to grow out of control and contribute to cancer developing.
Each cell has the ability to spot changes in DNA and fix them before they are passed on to new cells. Sometimes a cell’s ability to make these repairs fails and the change is passed on to new cells.
The cells that have damaged DNA are more likely to become cancerous. Several mutations usually have to occur before a normal cell changes into a cancerous one.
Some cancers are due to the genes we are born with. Other cancers are due to gene changes that happen during our lifetime.
Sporadic (acquired) cancers are due to mutations that happen as we get older or because of age, chance or something we are exposed to (carcinogen). Sometimes these mutations are errors that occur during cell division.
They can also be caused by something that damages the cell’s DNA. Mutations can affect the structure of the gene and stop it from working properly. The majority of cancers are sporadic (caused by acquired gene mutations).
Only a few cancers (again, about five to 10 per cent) are caused by inheriting a certain gene mutation. These are commonly referred to as inherited (hereditary) cancers, but this term is not very accurate. Cancer cannot be inherited. Instead, a particular gene mutation is inherited.
This mutation makes a person more susceptible or predisposed to developing cancer. Although inheriting the mutation increases the risk of developing cancer, it does not always mean that a person will definitely get cancer during their lifetime.
Often with hereditary
cancers, the person who develops cancer tends to develop it at an earlier age than the rest of the population.
I encourage you to visit cancer.ca to find out more about genetics and their impact on your cancer risk. It’s not as daunting as you may have thought.
Ivana Topic is a volunteer with Canadian Cancer Society, Quesnel office.