[The clinical significance of the Philadelphia chromosome in acute leukaemia (author's transl)].

So-called "Philadelphia-positive acute leukaemias" require varied therapeutic management. Additional chromosome anomalies together with Ph1 indicate an acute transformation of a Philadelphia-positive disease, requiring "non-myelotoxic" treatment and new therapeutic approaches. By contrast, "de novo" acute leukaemias with a Ph1-positive karyotype should be treated with intensive chemotherapy for the induction and maintainance of remission.