Philadelphia chromosome positive childhood acute lymphoblastic leukemia

In a 3-yr period, the Philadelphia (Ph¹) was found in 4 of 43 children with acute lymphoblastic leukemia (ALL) in whom chromosomes were studied at diagnosis. The clinical, morphological, cytochemical, and immunologic findings in the Ph¹-positive (Ph¹+) cases were consistent with typical childhood ALL, indicating that identification of cases requires chromosome studies. A review of all reported cases of Ph¹+ childhood ALL shows that Ph¹+ patients are older and have higher initial platelet and white blood cell counts (WBC) than most children with ALL. However, a life table comparison between the reported cases of pH¹+ ALL in children and randomly selected age-, sex-, and WBC-matched controls with ALL shows the duration on first marrow remission to be significantly shorter (p<0.02) for the Ph¹⁺ cases. Ph¹+ ALL is a distinct subtype of childhood ALL that is not rare and can be identified only by cytogenetic studies. The prognosis is poor. Cytogenetic studies should be done prospectively in a large group of children with ALL to define further this subgroup of patients and to confirm the findings of this retrospective analysis.