Major efforts included: (1) completing joint analyses from eleven cohorts of miners to refine estimates of risk from radon; (2) analyzing data on long-term risks of thyroid neoplasia following gamma radiation; (3) completing studies of lung cancer risk from domestic exposure to radon; (4) preparing reports on the design and exposure findings for a study of the effects of benzene exposure on risk of leukemia; (5) defining the role of human papillomavirus for risk of cervical intra-epithelial dysplasia; (6) describing long-term results for survivors of childhood cancer, including mortality excesses, learning disabilities and other problems; (7) developing methods to measure heterocyclic aromatic amines in epidemiologic studies; (8) analyzing data from vitamin interventions to prevent gastric and esophageal cancer; (9) investigating the usefulness of DNA ploidy in the management of patients with hydropic placentas and ovarian cancer; (10) validating the Breast Cancer Detection and Demonstration project model for predicting individualized risks of breast cancer; (11) using multivariate methods to estimate attributable risks for bladder cancer, gastric cancer and mesothelioma; (12) adapting backcalculation to accommodate treatment effects to project national AIDS incidence trends; (13) adapting backcalculation to study changing patterns in the age distribution of recent HIV incidence; (14) studying the spectrum of HIV related cancers by analyzing linked data from AIDS registries and cancer registries; and (15) applying spline methods to estimate the hazard function for AIDS and the rate of infection in cohorts of hemophiliacs.