Cytogenetic association and prognostic significance of bone marrow blast cell terminal transferase in patients with acute myeloblastic leukemia

One hundred ninety-two patients with previously untreated AML had TdT studies performed on their presenting BM aspirate specimens. Thirty-seven patients (19%) had greater than 5% TdT-positive (TdT+) blasts in their BM, as determined by an indirect immunofluorescence technique. CR rates were similar in both groups of patients (20/37 vs. 97/155, p = not significant) as were remission durations and median survivals. In the subset of patients younger than 60 years, patients with TdT+ blasts had an increased median survival (110 vs. 54 weeks, p = 0.1) compared with those having TdT- blasts. Six of 37 patients with TdT+ findings had t(8;21) translocations compared to 5 of 155 with TdT- findings (16% vs, 3%, p < 0.01). Patients with more than 50% BM blast cells showing TdT positivity at diagnosis tended to be younger than those with TdT- (mean age 30.5 years and 50.3 years, p = 0.04). The presence of TdT+ blast cells in the initial marrow in patients with AML may be associated with specific cytogenetic abnormalities and may identify subsets of patients who have improved prognoses.