"A City of Hopeled study found that the use of lowdose aspirin mg reduces the risk of breast cancer in women who are part of the Californias Teachers Study. This study  which is the first to suggest that the reduction in risk occurs for lowdose aspirin  was proposed by City of Hopes Leslie Bernstein Ph.D. professor and director of the Division of Biomarkers of Early Detection and Prevention and published online in the journal Breast Cancer Research.  Bernstein and her colleagues saw an overall  percent lower risk of breast cancer in women who reported using lowdose aspirin at least three times per week. Such regular use of lowdose aspirin reduced the risk by  percent of estrogen or progesterone receptor positive HER negative breast cancer which is the most common breast cancer subtype. The study found an interesting protective association between lowdose aspirin and breast cancer said lead author Christina A. Clarke Ph.D. M.P.H. from the Cancer Prevention Institute of California. We did not by and large find associations with the other pain medications like ibuprofen and acetaminophen. We also did not find associations with regular aspirin since this type of medication is taken sporadically for headaches or other pain and not daily for prevention of cardiovascular disease. This study differed from other studies that have looked at aspirin and cancer risk because it focused on the dose levels of the aspirin women had taken and tracked the frequency of the use of lowdose aspirin as opposed to regular aspirin. It was also able to look in detail at subtypes of breast cancer. We already knew that aspirin is a weak aromatase inhibitor and we treat women with breast cancer with stronger aromatase inhibitors since they reduce the amount of estrogen postmenopausal women have circulating in their blood said Bernstein. We thought that if aspirin can inhibit aromatase it ought to reduce the likelihood that breast cancer would develop and it could also be an effective way to improve breast cancer patients prognosis once they no longer take the more potent aromatase inhibitors. Bernstein added Aspirin also reduces inflammation which may be another mechanism by which aspirin taken regularly can lower risk of breast cancer developing or recurring.  As part of the study researchers analyzed data recorded in questionnaires submitted by  women in the Californias Teachers Study. In  participants answered questions regarding family history of cancer and other conditions use of aspirin and other nonsteroidal antiinflammatory drugs NSAIDS menstrual and reproductive history use of hormones weight and height living environment diet alcohol use and physical activity. In the ensuing years before   of these participants developed invasive breast cancer.  The team of researchers chose to focus on lowdose baby aspirin because not only is it inexpensive and readily available as potential means of prevention but because there are already a lot of people already taking it for prevention of other diseases such as heart disease and even colon cancer. Now that we have some data separating lowdose from higherdose aspirin more detailed research can be undertaken to understand the full value of lowdose aspirin for breast cancer prevention said Clarke.  Other collaborating authors include Alison J. Canchola M.S. and Lisa M. Moy M.P.H. from the Cancer Prevention Institute of California and Susan L. Neuhausen Ph.D. The Morris  Horowitz Families Professor in Cancer Etiology  Outcomes Research Nadia T. Chung M.P.H. and James V. Lacey Jr. Ph.D. M.P.H. from City of Hope. Research reported in Breast Cancer Research was supported through grants from the National Cancer Institute and the California Breast Cancer Research Fund under grant numbers R CA and . The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. About City of Hope  City of Hope is an independent research and treatment center for cancer diabetes and other lifethreatening diseases. Designated as one of only  comprehensive cancer centers the highest recognition bestowed by the National Cancer Institute City of Hope is also a founding member of the National Comprehensive Cancer Network with research and treatment protocols that advance care throughout the world. City of Hope is located in Duarte California just northeast of Los Angeles with community clinics throughout Southern California. It is ranked as one of Americas Best Hospitals in cancer by U.S. News  World Report. Founded in  City of Hope is a pioneer in the fields of bone marrow transplantation diabetes and numerous breakthrough cancer drugs based on technology developed at the institution."