Chromosome Studies in Potentially Leukaemic Myeloid Disorders

Fifteen patients suffering from various “non‐leukaemic” myeloid disorders have been cytogenetically investigated. Evidence is presented that chromosome abnormalities may be present in both the erythrocytic and granulocytic precursors of the bone marrow. On the basis of a review of the literature it is suggested that myeloid disorders with abnormal stemlines in the bone marrow should be considered neoplastic conditions. It is concluded that the abnormal chromosome complements may be present at a very early stage of the leukaemic process and that the emergence of the abnormal stem‐lines occurs prior to and is unrelated to the blastic transformation of the granulocytic precursors characteristic of myeloblastic leukaemia.