The Philadelphia chromosome (Ph1) in adults presenting with acute leukaemia: a comparison of Ph1+ and Ph1-patients.

To evaluate the frequency and clinical significance of the Philadelphia chromosome (Ph1) in adult acute leukaemia, bone marrow chromosomes were studied in 15 adults with acute lymphocytic leukaemia (ALL) and 55 with acute nonlymphocytic leukaemia (ANLL). Morphology, clinical findings, therapeutic response and survival were compared in patients with and without the Ph1. The Ph1 was found in six newly diagnosed adults presenting with ALL. Adults with Ph1+ ALL differed from those with Ph1-ALL in being older, in having more frequent lymphadenopathy and splenomegaly and in demonstrating higher initial leucocyte counts and more peripheral blasts. Complete remissions were obtained in all nine adults with Ph1-All but in only three of six with Ph1+ ALL. Adults with Ph1-ALL survived significantly longer. Four adults with ANALL were Ph1+. They did not respond to treatment and survived significantly shorter periods than adults with Ph1-ANLL. No clinical or morphologic features indicated which patients with acute leukaemia would have the Ph1. Since the presence of the Ph1 in acute leukaemia has therapeutic and prognostic significance, marrow chromosome studies should be performed in adults presenting with acute leukaemia, especially ALL.