Ann Tsukamoto

She figured out how to rebuild your blood after cancer.

In 1991, Ann Tsukamoto co-patented a method to isolate human hematopoietic stem cells (hHSCs).

These are the stem cells that form the entire blood and immune system.

And with it, came the potential to rebuild immune systems destroyed by cancer.

At the time, she was working at SyStemix, the first stem cell company.

Her discovery was a turning point: she proved that you could isolate hHSCs from the blood of patients who had already undergone myeloablative chemotherapy.

Even though their blood was cancer-contaminated, Tsukamoto’s method pulled out pure, regenerative cells.

These isolated stem cells were then reintroduced into patients and successfully rebuilt their blood-forming systems.

But Ann didn’t stop with blood.

After earning her Ph.D. in immunology and microbiology at UCLA, she did her postdoc at UCSF with Nobel Prize-winning scientist Harold Varmus.

There, she developed a transgenic model for breast cancer and studied the WNT1 gene, now known as a key player in the stem cell self-renewal pathway.

In 1998, she joined StemCells, Inc.

There, her team isolated the human central nervous system stem cell (HuCNS-SC®).

These cells showed promise for regenerating damaged neural tissue in the brain, spinal cord, and eye.

In early clinical trials, the data pointed to something medicine had never seen before: the ability to repair parts of the human nervous system.

Her team also identified a second candidate stem cell for the liver and advanced their research toward clinical applications in neurodegenerative diseases like Parkinson’s, Alzheimer’s, and spinal cord injuries.

Over her career, Tsukamoto secured a total of 13 U.S. patents:
- 6 related to human hematopoietic stem cells
- 1 on methods of gene transfers
- 4 related to enriched pancreatic stem and progenitor cell populations
- 2 on genome editing of human neural stem cells using nucleases

In 2023, the University of California San Diego awarded Ann the Changemaker Award, honoring her pioneering work isolating blood-forming stem cells.