"Spontaneous" erythroid progenitor cells in the circulation and monosomy 7 in juvenile chronic myelogenous leukemia

Cytogenetic examination of bone marrow cells from two patients with juvenile chronic myelogenous leukemia (JCML) showed a monosomy 7. Peripheral blood from these two children was found to contain large numbers of cells capable of erythroid colony formation in tissue culture without added erythropoietin. We conclude that erythroid progenitor cells are part of the malignant clone in JCML.