In collaboration with Tenwek Hospital in Bomet, Kenya, Kenyatta National Hospital in Nairobi, and the Mayo Clinic, NCI has begun a study to understand the risk factors and prevalence of esophageal squamous dysplasia (ESD) in Western Kenya. Investigators recruited 300 asymptomatic adult residents of villages within 50 km of Tenwek Hospital, and these individuals completed a risk factor questionnaire, gave blood and urine samples, and underwent transoral videoendoscopy of the esophagus with iodine chromoendoscopy and mapping and biopsy of identified lesions. Data analysis has begun. The results will guide the design of programs to screen and treat ESD as well as studies that will compare risk factors for ES and invasive esophageal squamous cell carcinoma among Kenyans.