Effect of Imatinib on Bone Metabolism in Patients With Chronic Myelogenous Leukemia or Gastrointestinal Stromal Tumors

Inclusion Criteria: * Patients with CML in chronic phase, accelerated phase based on cytogenetic abnormalities in addition to Philadelphia chromosome but with less than 5 % blasts, or GIST taking imatinib * Patients with life expectancy of at least 12 months; patients must be on imatinib at time of study entry. * Ability to sign informed consent and/or assent Exclusion Criteria: * Patients with a known parathyroid disorder; active thyroid disorder except stable, replaced hypothyroidism; Cushing's syndrome; uncontrolled diabetes mellitus (could have unexpected fluid, electrolyte and mineral shifts); sarcoidosis (elevated calcitriol levels from granulomata); hypercalcemia of malignancy (i.e., PTHrP-mediated or extensive bone mets);known tumor-induced osteomalacia; Paget's disease of bone; known X-linged or autosomal dominant hypophosphatemic rickets/osteomalacia; known renal tubular disease (e.g., Fanconi's syndrome); chronic GI malabsorption sydrome. * Patients taking oral calcium in excess of calcium 750 mg and Vitamin D 400 mg daily (ie, that contained in a single multivitamin). Patients taking more than these amounts may be eligible for this study if vitamin and mineral supplementation in excess of this is stopped for a minimum of 2 weeks prior to study entry. * Patients taking oral or intravenous steroids, calcitonin, any selective estrogen modulating agent such as tamoxifen or raloxifene, gallium nitrate, and other bone seeking radionuceotides, any calcimimetic agent s…