I believe it all ties in. See the 2 links below that were just in the news today and yesterday.
They are in regard to obesity (more aggressive bc and worse outcome) and exercise (lowers bc risk regardless of family history and whether thin or not).
These show many things. Obesity - more insulin and insulin growth factors in bloodstream, more estrogen in bloodstream, less availability of fat soluble vitamins (like Vitamin D). All the above also increases inflammatory responses.
Exercise (regardless of obesity) - lowers insulin growth factors, regulates insulin, lowers cholesterol (which is a precursor of all sex hormones. LDL (the "bad" cholesterol) increases inflammatory responses in the arteries. Cholesterol's precursor is prostaglandin which does cause inflammation, swelling and pain (the bad pathway of Omega 6 vs the better Omega 3).
I could go on and on but - I won't.
http://www.asco.org/ASCO/News/Cancer...eutersid=10149
http://www.asco.org/ASCO/News/Cancer...eutersid=10142