Cytogenetic and molecular characteristics and outcomes of adult patients with early T‐cell precursor acute lymphoblastic leukemia

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a recently identified high-risk subgroup of T-cell ALL in children. However, there have been conflicting reports and limited data have been reported in adult patients. We retrospectively analyzed the cytogenetic and molecular characteristics and long-term survival outcomes of adult patients with ETP-ALL versus non-ETP-ALL. We analyzed 58 patients (median age, 35 years [range, 18-76 years]) with newly diagnosed T-cell ALL who received a uniform remission induction and consolidation chemotherapy with suitable samples for genetic analyses. If a donor was available, all patients were recommended allogeneic hematopoietic cell transplantation (allo-HCT) for post-remission therapy. Out of 58 patients, 21 (36.2%) had ETP-ALL. Patients with ETP-ALL were older and had a higher proportion of complex karyotype than non-ETP-ALL. Additionally, more DNMT3A mutations were detected in ETP-ALL, whereas FBXW7 mutations and CDKN2A/CDKN2B deletions were found nearly exclusively in non-ETP-ALL. The overall complete remission (CR) rates were not different between ETP-ALL (95.2%) and non-ETP-ALL (81.1%) and subsequent allo-HCT proceeding rates in CR1 were 61.9% for ETP-ALL and 43.2% for non-ETP-ALL, respectively. The overall prognosis of patients with T-ALL was poor that estimated 5-year overall survival (OS) was 33.3% for ETP-ALL and 29.5% for non-ETP-ALL. In a subgroup analysis of patients treated with allo-HCT in CR1 (n = 29), 5-year OS was 53.8% for ETP-ALL and 55.4% for non-ETP-ALL. Our data showed molecular characteristics of ETP-ALL and non-ETP-ALL and revealed that intensive chemotherapy followed by allo-HCT for post-remission therapy can contribute to preserved survival outcome of adult patients with ETP-ALL.