To the Editor: Fearon et al. (July 3 issue)1 overinterpret their data. Their elegant work on clonal abnormalities in acute nonlymphocytic leukemia provides evidence that in some patients both blast forms and mature granulocytes are clonally related. The “preleukemic hypothesis” to which they redirect our attention is attractive and supported by their data. However, the authors do not demonstrate that leukemic blast cells can differentiate in vivo to mature peripheral-blood polymorphonuclear leukocytes. That is but one interpretation of their data, and it remains as untested as it was when a similar discussion appeared in the Journal in 1983.2 If one.
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