Finally, authors who are willing to look at the “good news” results from the WHI and to look at the hormone that is actually causing the increase in breast cancer – it’s the progestin, not the estrogen. As the authors state this is old news, in the WHI it was clearly shown that women who took estrogen only did have a decreased risk of breast cancer. Even though as the authors state that overall the reduction did not reach clinical significance, the message that is important is that estrogen alone did not INCREASE the risk of breast cancer. The only group that showed an increased risk of breast cancer was the group where estrogens were combined with progestin (an artificial form of progesterone).