Immunity and Cancer: what’s the link?
What is cancer?
Cancer is a word that strikes fear in all of us because it is the leading condition that affects life expectancy worldwide [1]. However, it is basically just another illness that we don’t know all the answers to. The fear aspect comes from the fact that it can happen randomly, with varying severity and may be life-threatening if not kept under control or detected early.
Cancers are growths made up of cells that have changed from normal to abnormal. Ordinarily, tissues have a controlled population of millions of cells that divide just enough to keep the tissue repairing itself in a controlled way. But cancer cells have lost this ability and keep dividing out of control. They can also transform into other types.
What causes it?
This is a complex problem, but we know that cancers form mainly because faulty mechanisms inside the cells, from the genetic code and how the information is read. These faults can be inherited (from family backgrounds), from damage caused by radiation (e.g. sun, xrays), viruses or chemical toxins. Many of these can come from the environment, unhealthy lifestyles or because of other health problems.
The problem is more complex because there are more than 120 different types [2], which can be at different stages of growth, and in one area or moving to other parts of the body.
How does it affect older people?
In general, cancers occur more frequently in older people [3]. Although natural aging doesn’t necessarily cause it, the processes that control cancer growth are shared by those that control aging. For example, cancers produce higher levels of free radicals, form because of mutations and epigenetic problems.
Since older people already have higher levels of these kinds of damage, and their tissues more senescent, the chances of getting a particular type of cancer are higher. For example, a slower repairing ability in the older intestine tissues increases the likelihood of developing colon cancer, versus at a younger intestine [4].
How do cancers fool the immune system?
The immune systems don’t just protect our body from foreign factors like viruses and bacteria. They also reduce the damaged caused by inflamed or injured tissue, and this includes cancer growths (tumors). Cancers are very smart, because it has been discovered that they have developed special ways to bypass the scrutiny of the immune system [5]. Since we know that the efficiency of immune system starts to decline with age, it may be that looking after immune system health could indirectly provide a protective mechanism.
Cancers are treated in several ways, by specialist doctors called oncologists. The objective is to kill the cancer cells without damaging the normal cells. This is usually done using anticancer drugs or radiation therapy, or combinations of them. The downside is that they also deplete the immune system. Newer ways of treating cancers are looking at trying to re-activate the immune system to recognize cancer cells and kill them. This is called cancer immunotherapy [6].
How can you protect immunity as you get older?
Since the Covid-19 pandemic, there has been a lot of focus on immune system health, especially in older people. Looking after immune system health relies on ensuring we maintain a healthy, active lifestyle as we age, including a balanced diet lower in saturated fats, sugars, salt and enriched for specific nutrients.
Countries like Japan and the Mediterranean provide some interesting examples of where longevity and cancer reduction may be linked. They often have better intake of traditionally used fresh fruits and vegetables, nuts and legumes, seaweeds [7], polyunsaturated oils [8] and fermented products [9], for example.
While there is currently no cure-all for cancer, we can take steps towards prevention by looking after our health better.
References
- https://www.who.int/news-room/fact-sheets/detail/cancer.
- https://www.cancer.net/cancer-types.
- White, M.C., et al., Age and cancer risk: a potentially modifiable relationship. Am J Prev Med., 2014. 46(3 Suppl 1): p. S7-15. doi: 10.1016/j.amepre.2013.10.029.
- Watanabe, K., et al., Age-related dysfunction of the DNA damage response in intestinal stem cells. Inflamm Regen., 2019. 39:8.(doi): p. 10.1186/s41232-019-0096-y. eCollection 2019.
- Chen, Y., et al., Epigenetics Regulates Antitumor Immunity in Melanoma. Front Immunol., 2022. 13:868786.(doi): p. 10.3389/fimmu.2022.868786. eCollection 2022.
- Melo, V., E. Bremer, and J.D. Martin, Towards Immunotherapy-Induced Normalization of the Tumor Microenvironment. Front Cell Dev Biol., 2022. 10:908389.(doi): p. 10.3389/fcell.2022.908389. eCollection 2022.
- Teas, J., The consumption of seaweed as a protective factor in the etiology of breast cancer. Med Hypotheses., 1981. 7(5): p. 601-13. doi: 10.1016/0306-9877(81)90004-9.
- Michalak, A., P. Mosińska, and J. Fichna, Polyunsaturated Fatty Acids and Their Derivatives: Therapeutic Value for Inflammatory, Functional Gastrointestinal Disorders, and Colorectal Cancer. Front Pharmacol., 2016. 7:459.(doi): p. 10.3389/fphar.2016.00459. eCollection 2016.
- Baruah, R., M. Ray, and P.M. Halami, Preventive and therapeutic aspects of fermented foods. J Appl Microbiol., 2022. 132(5): p. 3476-3489. doi: 10.1111/jam.15444. Epub 2022 Feb 16.
from an Expert Author
