New research reveals that premenopausal women who carry excess belly fat, or have a larger waist to hip size, may have an increased breast cancer risks for a specific type of breast cancer, estrogen receptor (ER) negative. Having body fat in this area was linked more strongly to the risk of this specific type of cancer than it was for the ER-positive variety or to breast cancer itself.In 2010, an estimated 207,090 U.S. women will have been told they have invasive cancer of the breast. Another 54,010 cases of non-invasive cancer will also have been diagnosed. The good news is that rates of breast cancer have been decreasing by almost 2% a year, as have death rates from the disease.Doctor’s know that many breast tumors are sensitive to the hormone estrogen, and pathology reports typically identify which type of cancer a patient has.Estrogen receptor negative cancer is diagnosed when the cancer lacks receptors for the female hormone estrogen, so this hormone doesn’t stimulate cancer growth.Estrogen receptor positive cancers are those where cell growth is influenced by estrogen, and are responsive to treatment with tamoxifen because this drug blocks the interaction between estrogen and the estrogen receptor.The research team acknowledged that body fat composition has a complicated relationship with the risk of cancer. Having a higher BMI for example, has been linked to a rise in the risk of postmenopausal breast cancer, but not premenopausal cancers.In the latest bit of research the team focused on data from over 116,000 women who were enrolled in a previous study who had waist and hip circumference recorded.It seems that premenopausal women who carry extra fat around the organs in the abdominal region are more likely to develop hyperinsulinemia (a pre-diabetic condition). Experiments in the lab have shown that insulin receptors can promote the growth of breast cancer cells.The fact that ER-negative breast cancer was more strongly linked to fat in the abdomen and the waist-hip ratio than ER-positive breast cancer makes experts think that the means by which body fat distribution somehow gets around the sex hormone pathways. The findings are the first to point out that an insulin related pathway related to belly fat may be involved in the development of breast cancer in premenopausal women.Many women notice an abundance of belly fat as they get older, especially after menopause. As you’ve heard, putting the pounds in this area is particularly unhealthy as compared to other parts of the body, increasing your risk of heart disease, diabetes and even some cancers. It seems that the fat cells in the abdomen don’t just sit there adding extra bulk; they are active and produce hormones and other substances that can impact your health.If you’re concerned about your breast cancer risks, and know you’re carrying excess belly fat, now’s the time to make changes in your diet and fitness routine. You may not see it all on the outside, but losing even a few pounds can have many positive impacts on your body and your health.