Obesity in Menopausal Women Promotes Breast Tumor Growth and Progression
According to a preclinical study published in Cancer Research, overeating and obesity stimulate breast cancer development and growth. It seems that overweight postmenopausal women can reduce their risk of breast cancer if they lose weight.
Paul S. MacLean, Ph.D., associate professor of medicine at the University of Colorado Anschutz Health and Wellness Center in Aurora, said that postmenopausal obese women have an increased risk of breast cancer than lean women. He added that the mechanisms underlying this are not fully understood.
Breast cancer is one of the most common cancers in women. According to the American Cancer Society, 200,000 new cases of breast cancer are diagnosed each year and approximately 40,000 women are estimated to die in 2012 from breast cancer. Causes of this increased incidence of breast cancer are due to modern lifestyle: smoking, oral contraceptives, exposure to various chemical carcinogens (polycyclic aromatic hydrocarbons, pesticides, etc.), obesity etc. It should be noted that there is a genetic transmission in some cases, the best known being the gene mutations BRCA1 and BRCA2.
It is important to note that breast cancer is a cancer that can be prevented and if treated properly and in time, it can be cured. There are several signs and symptoms that occur in breast cancer and that should alert women: the appearance of a lump in the breast, blood leaking from the nipple, nipple retraction, skin orange peel etc. Also, imaging investigations have an important role in the early detection of breast cancer. It is recommended that any woman over 40-50 years to perform a mammogram regularly.
Now, MacLean and colleagues have shown that obesity may promote tumor growth. They made oophorectomy in laboratory animals to induce obesity, which mimicked the metabolic changes that occur in women in menopause. At menopause, women tend to gain weight because they consume more food than they need. Then the researchers showed in rat models that obesity is a contributing factor to the development and growth of these tumors.
It was showed that lean rats store excess glucose that result from overfeeding in tissues such as liver, fat, muscle and healthy breast tissue, while obese mice failed to take over and handle excess glucose,and that this excess was used by breast tumors. In addition, the researchers showed that obese mice tumors have high levels of progesterone receptor and that metformin, an antidiabetic drug, reduced tumor burden in obese rats after surgical ovariectomy.