Ernest McCulloch

Ernest McCulloch co-discovered stem cells with James Till and subsequently applied the stem cell concept to leukemia, providing the first evidence that acute myeloid leukemia is organized as a hierarchy with self-renewing leukemia stem cells at the apex, decades before John Dick formally isolated these cells. His development of the colony-forming unit assay created the quantitative framework for measuring stem cell function that remains the standard approach in cancer stem cell research. His stochastic model of stem cell fate decisions influenced understanding of how cancer stem cells balance self-renewal and differentiation to maintain tumor growth.