Puerto Rico experiences high rates of oral and pharynx cancer. This study aims to identify sociodemographic, behavioral, nutritional, dental, and occupational risk factors for oral and pharynx cancer in Puerto Rico. Another purpose is to evaluate the role of human papilloma virus and biomarkers for malignancy and malignant transformation in biological specimens from cases and controls. This study has a population-based case-control design with more than 500 cases ascertained from the cancer registry in Puerto Rico. The more than 600 control subjects are identified using two sampling frames providing good coverage and representation of the general population: a geographic area frame and Medicare rosters. Case and control subjects are interviewed in their homes using a standardized questionnaire which obtains data on a wide range of risk factors. Medical record data is being abstracted on cases. Biological specimens are being obtained from selected study subjects. Specimens include a blood sample, a buccal cell scraping, a urine sample, and pathologic slides. With collaboration of several academic and commercial laboratories and experts, NIDR and NCI have been evaluating methods for collecting buccal scrapings and laboratory methods for evaluating the presence of human papillomavirus in buccal scrapings. Data will be analyzed to determine differences between cases and controls in potential risk factors and in the presence and levels of viruses and molecular markers for malignancy. This study will provide insights into the etiology of oral and pharyngeal cancer, and the reasons for the high incidence rates of these cancers in Puerto Rico.