Chronic myelogenous leukemia. Association with 45 XO Philadelphia chromosome karyotype and prolonged survival.

A 42-year-old man with chronic myelogenous leukemia for ten years was found to have a 45 XO Philadelphia chromosome karyotype in myeloid cells with normal 46 XY pattern in peripheral blood lymphocytes. This chromosome pattern has been postulated to be associated with delay in onset of blastic transformation. The prolonged survival of this patient, with only minimal initial chemotherapy and lack of symptoms for ten years, lends support to the concept that the missing Y chromosome may be associated with a favorable prognosis in Philadelphia chromosome-positive men with chronic myelogenous leukemia.