Canfit Exercise Physiology
15 Oct 2025
Breast cancer is the most prevalent form of cancer in the world. Accordingly, much research has been conducted on the progression of this type of cancer. As October is Breast Cancer Awareness, we decided to do a deep dive into the biology of breast cancer in attempt to understand the affects of exercise on a cellular level.
A combined effort by university researchers in Spain and Italy has identified 14 ‘hallmarks’ which are associated with the development of breast cancer. Physical exercise has been linked with beneficial results in several of these hallmarks, a few of which we have detailed below.
Hallmark: ‘Sustaining proliferative signaling’.
Cancer cells are able to modify the signals that regulate cell growth. Some hormones, such as estrogen and progesterone, participate in ‘cell proliferation signaling’. In other words, estrogen tells a cell it’s time to divide (proliferate). Cancer cells change how these hormones signal cells, allowing breast cancer to be established in the body. A clinical study conducted in Canada showed that “anaerobic exercise training for eight weeks (four sessions per week) reduces both tumor weight and cell proliferation.” The study also demonstrated that “Aerobic exercise reduces the expression of both estrogen and progesterone receptors... thus further acting as a protective factor against tumor proliferation and development”. From this study, we can see that exercising regularly may slow tumour growth even once it is already established.
Hallmark: ‘Evading growth suppressors’
Scientific research has shown that “physical exercise activates tumour suppressors and inactivates tumour promoters by hampering the establishment of a favourable microenvironment for cancer progression”. Tumour ‘suppressor genes’ and ‘oncogenes' are the primary genes related to cancer development and evolution.
Hallmark: ‘Evading Immune Destruction’
Tumour cells have the ability to evade the immune system, in particular ‘NK’ (Natural Killer) cells which would otherwise seek and destroy cancerous cells. However, studies show that “moderate physical activity recovers the immune function by increasing the number and activity of certain cells belonging to the immune system.” Exercise has been proven to enhance levels of NK cells in patients making it harder for cancer cells to evade.
Hallmark: ‘Tumour-Promoting Inflammation’
Inflammation is a defence mechanism which is activated by the body as a result of trauma or infection. Once the problem is resolved, the inflammation subsides. In the case of breast cancer, this can become a chronic condition. Studies have concluded that “repeated bouts of exercise result in a higher steady-state level of serum IL-6 that contributes to a reduction in chronic inflammation”. ‘ILS-6' levels being scientific jargon for inflammation in the body. If the levels are steady and not piquing, inflammation is reduced.
Further studies need to be conducted to clarify the benefits of exercise on the hallmarks of breast cancer, however from our brief investigation here we have found that, “In all of these biological hallmarks, it is evident that an active and healthy lifestyle—notably including physical exercise—following diagnosis and during therapy contributes to decreased cancer severity and reduced expression of tumour-sustaining markers” .
You will find the full academic article with a complete list of the hallmarks of breast cancer at the following url:
https://pubmed.ncbi.nlm.nih.gov/36612320/