Endogenous Hormones and Breast Cancer
Established in 1999
Data from over 15,000 women in over 20 studies worldwide
The Endogenous Hormones and Breast Cancer Collaborative Group conducts pooled analyses of endogenous (natural) hormones in relation to breast cancer risk. Scientists from 23 studies around the world are collaborating in this work, and the group is looking at the roles of oestrogens, androgens and growth factors in the aetiology of breast cancer.
The Endogenous Hormones and Breast Cancer Collaborative Group was established in 1999 with its secretariat in the Cancer Epidemiology Unit, and has so far met three times, in 2000, 2003 and 2012 (view photograph). The first publication from the group showed that the serum concentrations of oestradiol and other sex hormones in postmenopausal women are associated with an approximately twofold increase in breast cancer risk. The next publication showed that the increase in breast cancer risk observed among obese postmenopausal women may be explained by the relatively high serum concentrations of oestradiol in these women, a consequence of the conversion of androgens to oestrogens in the adipose tissue. In 2010 we showed that circulating insulin-like growth factor-I (IGF-I) is positively associated with the risk for breast cancer in both premenopausal and postmenopausal women, and that the association of IGF-I with risk appears to be restricted to breast cancers which are positive for the oestrogen receptor. In 2013 we showed that breast cancer risk in premenopausal women is also positively associated with circulating oestrogens and androgens.
Current work is looking at the relationships of prolactin with breast cancer risk among both premenopausal and postmenopausal women, and updated analyses for postmenopausal women are planned.