Factor Released During Exercise Helps Suppress Breast Cancer Tumors, Study Finds
Michelle Milliken
Exercise has been linked with many health benefits in cancer patients, including a reduced incidence of chemo brain, a boosted immune system response, and possibly a lower risk of metastatic cancer. Research has also found that exercise of any duration may be helpful for stage IV patients. A new study may have found a clue as to why this is.
Researchers at Texas A&M recently delved further into the link between exercise and cancer risk, finding that there's an unidentified factor released during exercise that suppresses signaling within breast cancer cells, which reduces tumor growth and can kill cancerous cells. The team says the findings, published in the journal Frontiers in Physiology, may challenge some of the notions about how exercise impacts cancer risk.
Amanda Davis, the study's first author and a clinical assistant professor at the university's School of Veterinary Medicine & Biomedical Sciences, says, "For this study, we took a deeper look into the relationship between people who exercise more and have less of a risk of cancer; previously, it was believed that there wasn’t anything mechanistically linked. Rather, it was just the general benefits seen in your body because of a healthy lifestyle. These data are exciting because they show that during muscle contraction, the muscle is actually releasing some factors that kill, or at least decrease the growth of, neoplastic (abnormal, often cancerous) cells."
To investigate these factors, the researchers studied rats as they ran on treadmills over a five-week period, with the incline gradually raised throughout that time. The training regiment was consistent with the American College of Sports Medicine's recommendations for people.
Throughout the study, the team found that these cancer cell-suppressing benefits only occurred alongside the presence of albumin, a carrier protein produced in the liver. This leads Davis to believe that these unidentified factors are likely carried through the blood by albumin. The researchers also learned that the factors involved are naturally present in the muscles and are released into the bloodstream regardless of a person's usual activity level or muscle development. Though they couldn't pinpoint the minimum time needed to produce these benefits, more factors were found to be released the longer a workout lasted.
While this study focused on the luminal A line of breast cancer, similar effects were found with other forms.
Davis says, "These are definitely exciting data we have concerning exercise and breast cancer. However, exercise is not a 100% guarantee. Further research in this area will help to identify why some people who work out regularly are still diagnosed with cancer.
"There have been many different signaling pathways indicated in cancer development. Therefore, more studies concerning what pathways are influenced by exercise will be needed to determine which types of cancers would benefit from exercise and which types would not."
However, she says the findings should encourage people to get about 30 minutes a day of moderate intensity exercise for at least five days a week. The Centers for Disease Control and Prevention says such exercises include fast walking, water aerobics, riding a bike on a relatively flat path, playing doubles tennis, or pushing a lawn mower.
