Lead author Professor Tim Key of the Cancer Epidemiology Unit at the University of Oxford said: 'While the link between higher levels of sex hormones and breast cancer is well established in older, postmenopausal women, it's much less clear what effect hormones have on cancer risk in younger, premenopausal women.
Sex hormones linked to breast cancer risk in women under 50
Research
23 July 2013
Premenopausal women with high levels of sex hormones in their blood have an increased risk of breast cancer, an Oxford University study suggests, though further research is needed to understand this link.