Bisphosphonates have become commonly used for preventing and treating osteoporosis [1] and, more recently, to reduce the risk of skeletal related events in cancer patients with bone metastases [2,3]. After initial clinical observations suggested bisphosphonates could favorably influence the course of breast cancer patients with bone metastases [4], both preclinical and clinical studies have aggressively addressed this issue. At present, a series of full-scale randomized clinical trials, planned to involve nearly 25,000 breast cancer patients, are underway to evaluate the role of bisphosphonates and other bone-targeted agents as potential additions to adjuvant therapy management [5]. Most recently, interest in the potential of bisphosphonates to influence breast cancer incidence as a component of primary prevention strategies have emerged as well [5]. In a series of articles in this journal, leaders in this field provide reviews and commentaries on the preclinical science in this area, the current clinical evidence and the definitive information which should emerge in the proximate future regarding the expanding role of bisphosphonates in breast cancer patient management. Doctor's Lipton, Costa, and Coleman present current evidence regarding bone marker use to guide antiresorptive therapy targeting bone [6]. They present data that urinary N-telepeptide of type I collagen (NTX) levels before and during bisphosphonate therapy pro