I can't say it for sure, but as an opinion of sorts it becomes at some point about the ratio of testosterone to estrogen. So even you have an estrogen that is normal for a man if it is higher up in the range, and the testosterone isn't that great, the ratio becomes low and this make it a "cancer area". This is also saying progesterone factors in because we need that to keep the ratio better, because progesterone reduces estrogen. In other words lower natural testosterone history, and the progesterone has to be sufficient to keep the T/E ratio say 10 or above, so progesterone becomes key to keeping cancer and BPH away.