|Inclusion Criteria:||1) Stage IV breast cancer metastatic to bone and/or bone marrow only.|
2) Age between 18 and 65 years.
3) ECOG performance score of 0, 1
4) Subjects with breast tumors with hormone receptor positive disease (ER+/PR+, ER+/PR-, or ER-/PR+) must have failed at least one hormonal-based therapy for bone only disease.
5) Subjects with breast tumors with hormone receptor negative disease must have failed at least one anthracycline and/or taxane-based therapy for bone only disease.
6) WBC >/= 3.5 x10^9/L, Hb >/= 10 g/dL, platelets >/= 100 x10^9/L.
7) Adequate pulmonary function defined as FEV1, FVC and DLCO (corrected for hemoglobin) >/= 50% of predicted.
8) Adequate cardiac function as evidenced by left ventricular ejection fraction (LVEF) of >/= 45%.
9) Serum total bilirubin < 2x ULN, and ALT/SGPT < 3x ULN
10) Creatinine clearance of >/= 75 mL/min for subjects up to 50 years of age, and adjusted for age by a 10% decrease per decade for subjects of more than 50 years of age.
11) Ability to understand the study and provide informed consent.