Men with naturally high levels of the female hormone oestrogen may have a greater risk of developing breast cancer, according to research by an international collaboration including Cancer Research UK published recently in the Journal of Clinical Oncology.
This is the first time a link between oestrogen levels in the blood and male breast cancer has been identified, despite its connection to breast, womb and ovarian cancers in women.
Men with the highest levels of oestrogen were two and a half times more likely to develop breast cancer than men with the lowest levels of the hormone.
Reference: Brinton et al. Prediagnostic sex steroid hormones in relation to male breast cancer risk. Journal of Clinical Oncology.