Prognostic significance of cytogenetical studies in chronic granulocytic leukaemia.

In a series of 121 patients with chronic granulocytic leukaemia (CGL) the frequence and prognostic significance of two cytogenetical features (absence of Ph'-chromosome and presence of Ph'-mosaicism) were studied. 13% of the patients were Ph'-negative, these patients showing a shorter survival than the Ph'-positive ones (P less than 0.005). 23 instances of Ph'-mosaicism were found (22.5%). This feature was observed either at diagnosis or after treatment, and irrespective of the patient's being in chronic or blastic phase of CGL, but in no case later than 2 years from diagnosis of the disease. Ph'-mosaicism patients vs the remainder of the Ph'-positive group were compared for survival, and no difference was found. The lack of prognostic significance of Ph'-mosaicism was evident regardless of the latter feature being detected at diagnosis or after treatment.