[Terminal DNA nucleotidyltransferase in blastic crisis in myelocytic leukemia].

The importance of determination of the activity of TdT is discussed in the light of a case of chronic myeloid leukaemia in a patient aged 55 years in whom after 4 years from the onset of the disease blastic crisis developed. High TdT activity was correlated with other features of blastic crisis of lymphoid character and with good response to vincristine and prednisone. This enzyme which is a valuable marker of lymphoblasts can predict also blastic crisis and give cues as to proper treatment.