Assessment of Tartrate-Resistant Acid Phosphatase (TRAP) as a Bone Resorption Marker in Stage IV Breast Cancer Patients With Bone Metastasis

Inclusion Criteria: 1. Histologic or cytologic documentation of breast cancer. 2. Stage IV Breast Cancer Patients with bone metastasis for whom Zometa treatment will be initiated. 3. Age \> 18 4. Written informed consent prior to study entry 5. Patients may be currently receiving hormone therapy, chemotherapy and/or radiation therapy to the primary tumor. 6. Life expectancy of at least 6 months. 7. We will include patients who have had previous or current radiation therapy to breast Exclusion Criteria: 1. Concurrent malignancy with a second primary 2. Stage I, Stage II and Stage III 3. ECOG Performance Status 3 or 4. 4. Renal Failure - serum creatinine \>2.O mg/dL at screening 5. AST or ALT \> ULN X 3. at screening 6. Bilirubin \> 3.0 mg/dL at screening 7. Pregnant women 8. Prior or current bisphosphonate therapy 9. Any skeletal related event due to malignancy prior to study enrollment. 10. Patients with osteoporotic fractures prior to study enrollment. 11. Allergy to bisphosphonates 12. Any radiation therapy for the treatment of bone metastases \<4 weeks prior to study start. 13. Any chronic medical condition which would preclude performance or adherence to protocol requirements 14. Inability to provide informed consent \-