Distinguished Scientist Award Recipients
Mark D. Johnson, M.D., Ph.D.
Brigham and Women's Hospital, Boston
2004 Distinguished Scientist Award
Education:
Amherst College, B.A., 1986, Chemistry
Harvard Medical School, M.D. & Ph.D., 1995, Medicine, Neurobiology
University of Washington, Seattle, 1995-2003, Resident, Neurological Surgery
University of Washington, Seattle, 1997-2003, Postdoctoral Fellow, Neuronal Apoptosis
-- Dr. Mark Johnson
About Dr. Johnson's Research:
The role of a novel putative human glioma tumor susceptibility gene, Peg3, in gliomagenesis and in determining the response to radiation and chemotherapy.
Peg3 is an important mediator of differentiation and p53-dependent cell death occurring after radiation or chemotherapy. However, the mechanism by which Peg3 mediates cell death is poorly understood. The Peg3 gene is located on chromosome 19q (a region that is often abnormal in gliomas), and is one of a small number of imprinted genes that is expressed exclusively from the father's copy of the gene under normal conditions. Peg3 expression is decreased in glioma cell lines due to abnormal genetic changes, and enforced overexpression of Peg3 decreases the ability of these cells to grow and form tumors. Although these data suggest that Peg3 may play an important role in brain tumor biology, none of these observations have been confirmed in patient tumor samples, and the relationship of Peg3 expression to the biology of these tumors in patients is not known. We present evidence for an inverse correlation between Peg3 mRNA expression and histologic tumor grade in gliomas, as well as preliminary evidence for genetic copy loss near the Peg3 locus in some glioblastomas. We hypothesize that Peg3 is a glioma susceptibility gene. This project will correlate Peg3 mRNA and protein expression in human gliomas with clinical outcome variables and will assess its prognostic/diagnostic significance. A search for hyper-methylation/mutations in the Peg3 gene will be performed, and the mechanism of Peg3-mediated cell death in gliomas will be investigated. Thus, Peg3 may represent a novel molecular target for the development of new prognostic tests or more effective therapies for gliomas.
Accolades:
"Mark possesses a unique set of intellectual and personal skills, which will greatly benefit the research he pursues in the field of Neuro-oncology. He is clearly among the elite of postdoctoral fellows and medical scientists I have encountered over the course of eighteen years of running my own laboratory. I would rank Mark as the single best resident I have ever trained."
--Richard S. Morrison, Ph.D.
University of Washington School of Medicine, Seattle
"Dr. Johnson's training to date has been obtained at some of the finest and most competitive institutions in the country, and his performance has been exceptional� He is an outstanding young investigator who is at a critical stage of his career, and the Sontag Distinguished Scientist Award will have a pivotal influence on his academic development."
-- Peter McL. Black, M.D., Ph.D.
Harvard Medical School, Boston
