Dr. Witte is recognized for multiple seminal contributions over the last 50 years impacting our understanding of human leukemias, immune disorders and epithelial cancers which have defined new targets for attack that have foreshadowed and strongly influenced the development of new therapies that have changed medical practice and patient outcomes.  His work on the Abelson murine leukemia virus oncoprotein aided the discovery of the tyrosine kinase class of enzymes. He discovered the Bcr-Abl protein as the product of the Philadelphia chromosome and showed it was necessary and sufficient to drive CML and some forms of ALL, validating Abl as a therapeutic target for tyrosine kinase inhibitor therapy leading to drugs like Imatinib which have revolutionized targeted therapy.  He discovered BTK as the cause of Bruton's agammaglobulinemia, and validated BTK as a therapeutic target for various B cell malignancies and autoimmune states which stimulated the creation of new targeted therapies like Ibrutinib that have transformed treatment for CLL, B cell lymphomas, multiple myeloma and certain autoimmune diseases. Dr. Witte expanded his interests to explore the pathogenesis of prostate and other epithelial cancers and discovered the Prostate Stem Cell Antigen (PSCA) which is under active investigation as a cell surface target for immune based treatment of advanced prostate and pancreatic cancers. Recent observations using a human epithelial tissue recombination/transformation system have shown that prostate and other tissues can be driven to an adenocarcinoma state by defined oncogenic signaling, and further trans-differentiated by epigenetic control to highly aggressive small cell carcinoma with neuroendocrine features which defines new immune targets for therapy under investigation. Dr. Witte is a member of the National Academy of Sciences, the National Academy of Medicine, the American Academy of Arts and Sciences, and the Cancer Research Academy of the AACR. He has served on the Board of Directors for the AACR, the President’s Cancer Panel, numerous editorial boards, and scientific advisory boards for academic centers and biotechnology companies. He was the founding director and for 15 years led the Broad Stem Cell Research Center at UCLA.  Dr. Witte has been recognized for his work by multiple awards including: The Richard and Hinda Rosenthal Foundation Award of the AACR; The William Dameshek Prize of the American Society of Hematology; The Warren Alpert Foundation Prize; The Leukemia and Lymphoma Society’s de Villiers International Achievement Award; The AACR G.H.A. Clowes Memorial Award; The Stanford Medical School Kornberg-Berg Lifetime Achievement Award in Biosciences; The AACR Award for Outstanding Achievement in Blood Cancer Research; and most recently The Harrington Prize for Innovation in Medicine.