Out of 239 women with breast cancer, almost 60% had a leukemia virus that came from contaminated meat, milk and cheese (compared to 29% in the blood of women without breast cancer). This research came out of UC Berkeley.

The most recent dairy study looking at herds that had this virus, came out in 2007. It found that over 82% of the entire US dairy herd from the nation’s 17 major dairy-producing states – nearly 84% of the cow’s blood – has this virus.

I do not know if eating organically protects against this virus or not. I am going to look into it. This virus may be a more powerful risk factor for breast cancer than obesity or excessive drinking.
This study suggested bovine leukemia virus presents higher odds for human breast cancer than obesity, alcohol consumption or synthetic postmenopausal hormones!