Individuals with, or at high risk of, cancer because of their personal, familial, or environmental histories are identified by healthcare worker referral or by personal inquiry. Relevant etiologic risk factor information is documented through review of pathology specimens and medical, vital, and genealogical records. Selected individuals and family members are asked to complete questionnaires and to undergo clinical evaluations specific for the tumor of interest. They are also asked to donate biologic specimens to be used in the search for cancer etiology and mechanisms of carcinogenesis. No therapy beyond counseling and education for cancer prevention, risk reduction, and early detection will be given.