Two serious adverse events were detected (one case of breast cancer and one case of estrogen receptor–negative endometrial cancer), which was less than the expected population rate for these cancers.

Interesting study.  I am glad to see that more and more evidence is coming out on the safety of soy.  Maybe it will put all the bogus anti-soy propaganda to rest.

One thing that I disliked about the study though was this claim:

"Two serious adverse events were detected (one case of breast cancer and one case of estrogen receptor–negative endometrial cancer), which was less than the expected population rate for these cancers."

Why are they making soy out to blame when soy has nothing to do with these cancers? Both of these cancers have been positively linked to human papilloma viruses (HPV).  This is actually a good example of how some studies get manipulated.  If the researchers are looking for a link to begin with they will only look at possible associations and ignore other factors, even if known.  If I wanted to prove oxygen caused cancer I could just as easily claim that 100% of people that ever developed cancer breathed air so therefore oxygen causes cancer.  Of course oxygen does not cause cancer, but it demonstrates how easily casual association can be falsely attributed to a disease.  But presence of does not always mean cause of.