On the myeloblast as initiator of certain human leukemias

We reconsider the proposal that a stem cell (SC) is the initiator of clonal (human) leukemias. Using chronic myeloid leukemia (CML) as an example, we discuss some conceptual and experimental inconsistencies of the above conjecture. As an alternative, it is proposed that CML is initiated by an immature myeloblast. The main idea is that CML results from certain growth-related accidents encountered along the myeloid differentiation path. Retrodifferentiation of (semi) autonomous myeloblasts back to the SC state seems the principle cause for the distribution of clonal markers across all hemopoietic lineages, including those that are not involved in the leukemic process.