Dr. Humphrey is a practicing surgical and urologic pathologist, with a research focus on clinico-pathologic and molecular pathologic aspects of prostate cancer. He is on the editorial boards of The American Journal of Surgical Pathology, Modern Pathology, and Human Pathology. He has 361 publications, has authored the textbook Prostate Pathology, co-authored the textbook Gleason Grading of Prostate Cancer, co-authored the AFIP Fascicle on the Prostate, co-authored the textbook Neoplastic Mimics in Genitourinary Pathology, is co-editor of The Washington Manual of Surgical Pathology, and is co-editor of the 2016 World Health Organization book on Classification of Tumors of the Urinary System and Male Genital Organs . He is past President of the International Society of Urological Pathology and is past President of The Arthur Purdy Stout Society of Surgical Pathologists. He has given lectures on 6 of the 7 continents.