 - Individuals with a history of an invasive malignancy are ineligible except for the following circumstances: a individuals with a history of invasive malignancy are eligible if they have been disease-free for at least 3 years and are deemed by the investigator to be at low risk for recurrence of that malignancy; b individuals with the following cancers are eligible if diagnosed and treated - carcinoma in situ of the breast, oral cavity or cervix and basal cell or squamous cell carcinoma of the skin 