Women who struggle with obesity are at higher risk for breast cancer, and a look at hormones like estrogen and androgen is providing some possible explanations. A recent study by the University of Colorado Cancer Center and CU School of Medicine examined obese rats with breast cancer and found some important insights. The tumor cells in these animals had especially sensitive androgen receptors as compared with leaner rats. This allowed those cells to amplify growth signals from testosterone. The tumors of the obese rats grew due to androgen receptor activity.
Estrogen less of a factor in breast cancer for obese women
Women, dealing with obesity, often show aggressive tumor growth even after anti-estrogen treatment. Why is that? The study results (below) may provide the answer. Rats do not have the same mechanism regarding estrogen production from fat tissue as humans. This provided an ideal opportunity for the researchers to study the progression of cancer following anti-estrogen treatment. And, what they discovered was quite interesting. They were able to glean insights about what might be driving tumor progression in obese humans with low estrogen. As much as 40 percent of women in the U.S. are obese, and 75 percent of breast cancers are estrogen-receptor positive, meaning they are often treated with anti-estrogen therapy. Androgen receptors and testosterone are known prostate cancer drivers. The CU Cancer Center research and other studies are indicating that androgen could be the ‘driving force’ in many types of breast cancer.
Note: when obese rats with breast cancer were treated with enzalutamide, an anti-androgen treatment, their tumors shrank and new ones did not form.
Breast cancer worsens with inflammation and androgen production
What creates overactive androgen receptors and makes them more sensitive to the hormone testosterone? It can vary depending on the state of health of the individual, but some causes include high blood sugar, insulin resistance and chronic low-grade inflammation in the body. Persons who are obese tend to be high in interleukin 6 (IL-6), a cytokine linked with high levels of inflammation. Giving IL-6 to subjects with breast cancer stimulates androgen receptor activity. Obesity creates conditions of high inflammation – which is associated with elevated IL-6 levels. This in turn sensitizes androgen receptors and amplifies signals which drive the growth and spread of breast cancer – even in internal environments with low estrogen.
Diet and exercise is crucial to avoiding cancer
The insights from this study will influence breast cancer treatment choices for persons with obesity. The results were published in the journal Hormones & Cancer. And, of course, the data underscores the importance of maintaining a healthy weight to reduce the risk of chronic disease. Avoiding sugar and processed food is a must – in terms of living an anticancer lifestyle, as is a regular routine of aerobic exercise and strength training. Keep in mind: a meta-analysis study of 1.44 million participants showed regular exercise can lower the risk for 13 cancer types. In fact, just 20 minutes of brisk walking per day can make a significant difference to overall health.
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