The Philadelphia Chromosome (Ph1) in Adults Presenting with Acute Leukaemia: a Comparison of Ph1+ and Ph1‐ Patients*

Abstract

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 ANLL 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.