Dr. Meltzer is an internationally renowned leader in the molecular pathobiology of gastrointestinal malignancy and premalignancy. He invented molecular methods to detect loss of heterozygosity in tiny biopsies, triggering an avalanche of research on precancerous lesions. He was the first to comprehensively study coding region microsatellite instability, leading to the identification of several important tumor suppressor genes. He performed several groundbreaking genomic, epigenomic and bioinformatic studies of esophageal and colonic neoplasms, shifting the GI research paradigm toward genome-wide approaches. He directed an ambitious nationwide validation study of DNA methylation-based biomarkers for the prediction of neoplastic progression in Barrett’s esophagus. Dr. Meltzer founded and led the Aerodigestive Cancer and Biomarker Interdisciplinary Programs at the University of Maryland, also becoming associate director for core sciences at that school’s Cancer Center. He currently holds an endowed professorship and is the director of GI biomarker research at Johns Hopkins. The laboratory group focuses its efforts on the molecular genetics of gastrointestinal cancers and premalignant lesions, as well as on translational research to improve early detection, prognostic evaluation, and treatment of these conditions. Below, some examples of this work are described.