"Use of Antihypertensive Medications and Breast Cancer Risk Among Women Aged 55 to 74 Years"
JAMA IM  Aug 5
http://archinte.jamanetwork.com/article.aspx?articleid=1723871 
"Conclusions and Relevance  While some studies have suggested a positive association between calcium-channel blocker use and breast cancer risk, this is the first study to observe that long-term current use of calcium-channel blockers in particular are associated with breast cancer risk. Additional research is needed to confirm this finding and to evaluate potential underlying biological mechanisms."