 No other medical contraindications to stem cell donation i.e. severe atherosclerosis, autoimmune disease, cerebrovascular accident, prior malignancy. Patients with a history of coronary artery bypass grafting or angioplasty will receive a cardiology evaluation and be considered on a case-by-case basis. Persons with a history of non-hematologic malignancy must have undergone potentially curative therapy for that malignancy and 1 have had no evidence of that disease for 5 years, andor 2 be deemed at low risk for recurrence less than or equal to 20 at 5 years. Such persons will be considered eligible for stem cell donation at the discretion of the principal investigator. Prospective donors with a history of non-hematologic malignancy who have received potentially curative therapy and are in remission, but whose estimated risk of recurrence is greater than 20 at 5 years, will be considered on an individual basis in consultation with the NCI IRB. 