Breast cancer is one of the most prevalent cancers with 207,090 new cases of breast cancer and 39,840 deaths in women predicted for 2010 in the United States(1). Aromatase inhibitors (AIs) are used as first-line adjuvant therapy for postmenopausal women with early stage breast cancer(2). The effectiveness of current therapy is widely recognized to be compromised by poor compliance because of aromatase inhibitor-associated musculoskeletal symptoms (AIMSS), a syndrome that affects up to 40-50% of women who take these medications. The syndrome that was not recognized during the registration trials for this class of drugs(3), it can lead to discontinuation in up to 24% of women over 2 years (4,5). Knowledge that can be used to prevent discontinuation of these important agents because of severe AIMSS is urgently needed.