In Reply.—The remarks of Dr Inoue and colleagues are important and suggestive of underlying host alteration in some cases of second malignancy. These authors and their co-workers have contributed greatly to our knowledge of the cytogenetic changes in malignant disease. We have had a preoccupation with classifying leukemia. One of us (P.J.T.) has observed a recent case consistent with the remarks of Dr Inoue and colleagues on juvenile-type CML. A 2-year-old boy had a typical Ph1-negative, juvenile CML and elevated fetal hemoglobin values. A brief remission was induced; the next relapse was erythroleukemia. A second remission was achieved. The second relapse was histochemically confirmed acute monocytic leukemia. Dr Inoue and associates would probably agree with us that this "three-in-one hit" represents three phases of one leukemia.
Transmissible, oncogenic nucleoprotein, such as the bacterial plasmid factors in ampicillin-resistant Escherichia and Salmonella, may be operative in leukemias that cross different