Decreased activity within the Transforming Growth Factor Beta (TGF-beta) pathway is associated with increased breast cancer risk, according to a study published by researchers at Northwestern Memorial Hospital and Northwestern University’s Robert H. Lurie Comprehensive Cancer Center in today’s Cancer Research journal. This is the first study aimed at determining whether various combinations of two naturally-occurring variants of the TGF-beta pathway may predict breast cancer risk. It is also the first study assessing a cancer-related pathway by means of two functionally-relevant variants. Blood tests were performed on 660 patients with breast cancer and 880 healthy females for two TGF-beta variants: TGFBR1*6A and TGFB1 T29C. “Our study shows that TGFBR1*6A is associated with a 120 percent increased risk of breast cancer among women older than 50,” says study author Boris Pasche, MD, PhD, FACP, director of Northwestern’s Cancer Genetics Program and assistant professor of Medicine at Northwestern University’s Feinberg School of Medicine. “Importantly, the results show that women with the lowest levels of TGF-beta activity have a 69 percent higher risk of breast cancer than women with the highest levels of TGF-beta activity as predicted by the combination of the two variants TGFBR1*6A and TGFB1 T29C. This finding is promising as it may eventually help us predict breast cancer risk in a large subset of the population. Indeed, breast cancer risk may be predicted in 30 percent of women through assessment of the TGFBR1*6A and TGFB1 T29C variants.”