Dr. Geraldine Canny:

It is multifactorial.

Certainly there is a genetic component. It is clear that it is heritable through generations. With respect, we have already alluded to the fact that there is a an overproduction of oestrogen in the lesions and there is an overproduction of inflammatory mediators. It is thought that another potential risk factor is in endocrine disrupters, which are increasingly present in food, water and the environment. Such molecules, which are structurally diverse, can activate oestrogen receptors. These have, in some incidences, been posited to play a role in the pathology. This, however, is very difficult to prove per se.