http://www.express.co.uk/posts/view/255448/Sunlight-stops-breast-cancer

Vitamin D is a weapon against breast cancer:

WOMEN who spend just three hours a day in the sunshine can cut their risk of developing breast cancer in 1/2.

here's another article:

http://www.businessweek.com/lifestyle/content/healthday/652370.html?campaign_id=rss_topStories

Breast cancer patients with low levels of vitamin D have more aggressive tumors and poorer outcomes, a new study finds.