The “C-word” is one that nobody ever wants to hear in their lifetime. But what is cancer and how does it all start? The next few paragraphs offer a brief understanding of how cancer develops in the body.
Let's start at the very beginning:
Normally, cells from different parts of the body are regulated through various mechanisms which remove or replace ageing and abnormal cells. When this regulation is lost (due to many reasons) it gives rise to an overgrowth of abnormal cells which are capable of spreading to other parts of our body.
In simple terms, “Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body”.(1)
Is Cancer genetic?
Yes. Cancer is a genetic disease.(2)
BUT…Let's pause right now…I said genetic, NOT Hereditary! We’ll come back to this in a bit…
Cancer is genetic because genes code (send instructions) for proteins that are required for optimal functioning of our cells. So, when a gene undergoes a mutation (change in the DNA sequence), the protein that it codes for along with the functioning of the cell also undergoes change. This happens to many cells in our bodies on a daily basis and can have two fates:
The immune system may recognize these cells and take care of them, keeping us cancer free.
The cancer cells may heap up and undermine our immune system, resulting in cancer.
What makes genes mutate?
Genes that make us cancer prone can be either inherited from our parents or developed due to external factors. Incidentally, only 5 to 10% of cancers are hereditary. This means that only 5 to 10% of us can blame our parents for passing on genes that make us susceptible to cancer. The remaining 90 to 95% of cancers are triggered by lifestyle and environmental factors such as obesity, lack of physical activity, dietary factors, smoking, alcohol, stress, sleep disturbances, radiation, environmental pollutants, etc. In fact, of all cancer-related deaths, approximately 30%, 25% and 15% are linked to diet, tobacco and infections, respectively.(3) This implies that 90 to 95% of those who have cancer could have contributed to its development!
A special word of caution about using the label of "hereditary" for a cluster of family members with cancer. This is because it is possible that all the members of a family share a similar cancer risk due to common lifestyles and/or are exposure to same environmental toxins.
Bottom line:
Yes, cancer is in your genes; BUT at least 9 out of 10 times lifestyle and the environment are responsible for activating gene mutations that lead to cancer!
The good news is that if lifestyle can create, lifestyle can also prevent!
Look out for my series on Cancer Prevention through Lifestyle
References:
What is Cancer: National Cancer Institute: Available from: https://www.cancer.gov/about-cancer/understanding/what-is-cancer. Accessed May 2022
The Genetics of Cancer: National Cancer Institute: Available from: https://www.cancer.gov/about-cancer/causes-prevention/genetics#:~:text=Inherited%20genetic%20mutations%20play%20a,individuals%20to%20developing%20certain%20cancers. Accessed May 2022
Anand, Preetha et al. “Cancer is a preventable disease that requires major lifestyle changes.” Pharmaceutical research vol. 25,9 (2008): 2097-116. doi:10.1007/s11095-008-9661-9