# Ann Tsukamoto

Ann S. Tsukamoto Weissman (born July 6, 1952) is an Asian American stem cell researcher and inventor. In 1991, she co-patented a process that allowed the human stem cell to be isolated and demonstrated their potential in treating patients with metastatic breast cancer. Tsukamoto has received a total of 13 patents in her career, the majority of them having to do with human hematopoietic stem cells.
Tsukamoto’s research and contributions in the medical field have led to groundbreaking advancements in stem cell research, especially in understanding the blood systems of cancer patients. Her work has shown potential treatments for cancers and neurological disorders, for which there were previously thought to be none.

## Career

Ann Tsukamoto was born in California on July 6, 1952. She completed her bachelor's degree at the University of California San Diego and her Ph.D in immunology and microbiology at the University of California Los Angeles. Tsukamoto did most of her postdoctoral work at the University of California, San Francisco. Here, she worked on the wnt-1 gene and developed a transgenic model for breast cancer. Wnt-1 was later discovered to be a key player in the stem cell self-renewal pathway. She joined the biotech company SyStemix from 1989 to 1997, where she co-discovered the human hematopoietic stem cell (hHSC) and played a leading role in the launch of the clinical research program for this cell. The purified hHSC was shown to be cancer-free when isolated from the cancer-contaminated hematopoietic mobilized blood of patients with disseminated cancer, and it successfully regenerated the patients' blood-forming system after myeloablative chemotherapy. Tsukamoto joined StemCells Inc. in 1998, where she has held several leadership roles overseeing the isolation and application of human neural and liver stem cells for various diseases. She led the scientific team that discovered the human central nervous system stem cell and identified a second candidate stem cell for the liver. Under her guidance, the human neural stem cell transitioned into early clinical development for all three components of the central nervous system: the brain, spinal cord, and eye. The biological potential and activity of these cells were demonstrated in some patients, mirroring the results observed in preclinical rodent studies.
As of 2017, Tsukamoto is an inventor on seven issued U.S. patents, six of which are related to the human hematopoietic stem cell. By 2021, she had reached a total of 13 patents. Aside from her accomplishments in patent applications and grants, in 2023 she was awarded with the Changemaker Award from her alma mater (University of California San Diego) for her breakthrough in isolating blood stem cells.

## Patents

Out of her 13 patents, 7 were grants with 6 that revolved around human hematopoietic stem cells (October 1991-June 1999). The other grant being for methods of gene transfers (July 1999). The other 6 patents were applications, 4 on enriched pancreatic stem cell (September 2006-March 2011) and progenitor cell populations and 2 on genome editing of human neural stem cells using nucleases (October 2017-August 2023).