Philadelphia chromosome in acute leukemia: case report.

A case report of serial chromosome studies on a child presumed to have acute lymphoblastic leukemia (ALL) is presented. Hematologic remission was achieved after 3 weeks and maintained until death 63 weeks later. The classic Philadelphia chromosome translocation was found, both at diagnosis and throughout the course of the disease, in a proportion of cells from PHA-stimulated blood cultures. The finding is related to other reports of Philadelphia-positive clones in ALL, as well as those in chronic myeloid leukemia and its acute transformation, and other myeloproliferative disorders. The origin of the Philadelphia chromosome in this case is considered in the light of current stem cell theory, and its relevance to lymphocytic neoplasia is discussed. We believe that the finding of a Ph1-positive clone in a cell line morphologically indistinguishable from normal lymphocytes in a case of acute leukemia is unique.