Irving Weissman

Irving Lerner "Irv" Weissman (born Great Falls, Montana, October 21, 1939) is a Professor of Pathology and Developmental Biology at Stanford University where he is the Director of the Stanford Institute of Stem Cell Biology and Regenerative Medicine along with Michael Longaker.

Weissman was raised in Great Falls, Montana and started his scientific career at the McLaughlin Research Institute there. He obtained his MD from Stanford University in 1965 after earning a BS from Montana State University in 1961. His research has since focused on hematopoietic stem cell biology.

Weissman was not an exceptionally good student in high school. He started assisting with medical research in 1956, when he got a summer job at Montana Deaconess Hospital. He preferred the idea of caring for laboratory mice and assisting in the lab to washing cars or similar jobs that were available to teenaged boys in the area. He was inspired by the idea that he could think scientifically and respond to a questioning, Socratic method, rather than didactic lectures about scientific facts. He ran his first experiment there during his senior year in high school, to see whether he could repeat an experiment that had recently been published. He attributes his admission to college and medical school to the resulting publications, rather than to his less-than-perfect grades.

His awards include election to the National Academy of Sciences in 1989, and being named California Scientist of the Year in 2002.

• 2008 Robert Koch Prize
• 2009 Rosenstiel Award [1]
• 2013 Max Delbrück Medal

He developed methods to identify stem cells, and has extensively researched stem cells and progenitor cells. His research focus is "the phylogeny and developmental biology of the cells that make up the blood-forming and immune system." Weissman is widely recognized as the "father of hematopoiesis", in which he is the first to purify blood forming stem cells in both mouse and humans. His laboratory was able to purify stem cells from other mature cells like B cells by taking advantage that each immune cell type expresses different lineage markers. Therefore, when mice immune cells were reacted with fluorescently labeled antibodies specific for effector cells, the mature cells were differentiated from the forming stem cells. His work has contributed greatly to the understanding of how a single hematopoietic stem cell can give rise to different specialized blood cells.

Weissman is also a leading expert in the field of cancer stem cell biology, where his work has shed light on the understanding of the pathogenesis of multiple human malignancies. He is known also for transgenic research in which human brain cells were grown in mouse brains.