About Us
Bitterroot Foundation is the philanthropic vision of Drs Irving Weissman and Ann Tsukamoto Weissman to enable affordable, life-saving treatment options for cancer and many other serious health conditions. As a nonprofit organization, Bitterroot Foundation will safeguard its purified stem cell technologies and offer non-exclusive licensing, and no licensing fees needed for research or clinical trials, to ensure that these transformative therapies remain affordable and accessible to all.
Our Founders
Irving Weissman MD
Dr Irving Weissman is one of the world's foremost experts in stem cell biology and regenerative medicine. As a leader in the field, he was the first to isolate pure hematopoietic stem cells in both mice and humans, work that revolutionized our understanding of blood and immune system development and opened the door to curative therapies for cancer, degenerative diseases, and other health conditions. Dr Weissman has spent decades advancing stem cell science from the laboratory to the clinic, leading to pivotal discoveries about cancer stem cells, immune tolerance, and tissue regeneration. His career reflects a lifelong commitment to translating stem cell science into real-world therapies and he continues to be a driving force in the pursuit of life-saving and affordable therapies for patients worldwide.
Ann Tsukamoto Weissman PhD
Dr Ann Tsukamoto Weissman is a globally recognized leader in stem cell research, she co-patented the process for isolation of human hematopoietic stem cells, a breakthrough that established the foundation for modern regenerative medicine and stem cell-based cancer therapies. With decades of experience in both research and biotechnology, she has led efforts to translate cutting-edge science into real-world clinical applications. Her work has contributed to multiple stem cell therapies and continues to influence the next generation of treatments for cancer and other serious conditions including central nervous system injuries, neurodegenerative disease, neurological disorders, and eye disorders. Dr Tsukamoto Weissman is deeply committed to advancing life-saving stem cell based therapies for all.
Awards / Recognitions
Irving Weissman
Wallace H. Coulter Award for Lifetime Achievement in Hematology, 2022
Distinguished Fellow of American Association of Immunologists, 2019
The Albany Medical Center Price in Medicine and Biomedical Research, 2019
Charles Rodolphe Brupbacher Prize for Cancer Research, 2015
Robert Koch Award, Koch Foundation, 2008
California Scientist of the Year, 2002
Member, Institute of Medicine, 2002
Member, National Academy of Sciences, 1989
Co-Founder: Pheast Therapeutics, Forty Seven, Inc., Cellerant, Inc., Stem Cells, Inc., SyStemix, Inc., 48 Bio
Scientific Advisory Board: Amgen Inc., Orca Bio, Appia Bio, Pheast Therapeutics, UKRMP Immunomodulation Hub, Gladstone Institutes, Institute of Medical Biology, A*STAR Singapore, Institute for Systems Biology, National Cancer Institute, Memorial Sloan Kettering Cancer Center
Ann Tsukamoto Weissman
Women Inventor of the Year Award, 1993
Changemaker Award, UC San Diego, 2023
In Montana, in the right season, the meadows of the Bitterroot Range are covered in Bitterroot — a low-lying plant with pale pink flowers. After losing its leaves, it recedes to the roots and then regenerates into a single brilliant bloom. The name Bitterroot Foundation is inspired by nature’s own cycles of renewal, and like the Bitterroot in bloom, the Foundation envisions a future where regenerative therapies are accessible to all who need them.
