Karlheinz Seeger

Activation of the HIF pathway in childhood ALL, prognostic implications of VEGF.

Hypoxia-inducible factor 1 (HIF-1) controls angiogenesis and glycolysis, two leading characteristics of solid tumor invasion, metastasis, and lethality. Increased angiogenesis is also found in the bone marrow (BM) of leukemias. Less is known in leukemia about the role of HIF-1 and vascular endothelial growth factor (VEGF), the most important proangiogenic target gene of HIF-1. We show by immunohistochemistry that the oxygen-regulated component of HIF-1 (HIF-1α) is overexpressed in clusters of leukemic cells in BM specimens of childhood acute lymphoblastic leukemia (ALL) and absent in biopsies of normal BM. Half the HIF-1α-positive ALL biopsies exhibited VEGF coexpression. Among 96 children with relapsed ALL, diagnostic BM aspirates with high VEGF mRNA levels were associated with a significantly lower probability of event-free survival at 3 years (0.31±0.08 vs 0.65±0.07, P=0.003). Those with poor molecular response to therapy (evaluated by MRD assessment) had 2.2-fold higher VEGF levels than those responding well to chemotherapy (P=0.005). In conclusion, the data demonstrate activation of the HIF pathway in the BM of ALL patients and indicate that the expression of HIF target genes, such as VEGF, play an important role in leukemia progression, therapy response, and outcome.

Use of Allogeneic Hematopoietic Stem-Cell Transplantation Based on Minimal Residual Disease Response Improves Outcomes for Children With Relapsed Acute Lymphoblastic Leukemia in the Intermediate-Risk Group

PURPOSE In children with intermediate risk of relapse of acute lymphoblastic leukemia (ALL), it is essential to identify patients in need of treatment intensification. We hypothesized that the prognosis of patients with unsatisfactory reduction of minimal residual disease (MRD) can be improved by allogeneic hematopoietic stem-cell transplantation (HSCT). PATIENTS AND METHODS In the Acute Lymphoblastic Leukemia-Relapse Study of the Berlin-Frankfurt-Münster Group (ALL-REZ BFM) 2002, patients with an MRD level of ≥ 10(-3) (n = 99) at the end of induction therapy were allocated to HSCT, whereas those with an MRD level less than 10(-3) (n = 109) continued to receive chemotherapy. MRD was quantified by real-time polymerase chain reaction for clone-specific T-cell receptor/immunoglobulin gene rearrangements. RESULTS The probability of event-free survival for patients with MRD ≥ 10(-3) was 64% ± 5% in ALL-REZ BFM 2002 compared with 18% ± 7% in the predecessor study ALL-REZ BFM P95/96 (P < .001). This was mainly achieved by reducing the cumulative incidence of subsequent relapse (CIR) at 8 years from 59% ± 9% to 27% ± 5% (P < .001). The favorable prognosis of patients with MRD less than 10(-3) could be confirmed in those with a late combined or isolated bone marrow B-cell precursor (BCP) -ALL relapse (CIR, 20% ± 5%), whereas patients with an early combined BCP-ALL relapse had an unfavorable outcome (CIR, 63% ± 13%; P < .001). CONCLUSION Allogeneic HSCT markedly improved the prognosis of patients with intermediate risk of relapse of ALL and unsatisfactory MRD response. As a result, outcomes in this group approximated those of patients with favorable MRD response. Patients with early combined relapse require treatment intensification even in case of favorable MRD response, demonstrating the prognostic impact of time to relapse.

TEL-AML1 POSITIVITY IN RELAPSED B CELL PRECURSOR ACUTE LYMPHOBLASTIC LEUKEMIA IN CHILDHOOD

TEL-AML1 positivity in relapsed B cell precursor acute lymphoblastic leukemia in childhood

Monitoring minimal residual disease in children with high-risk relapses of acute lymphoblastic leukemia: prognostic relevance of early and late assessment

The prognosis for children with high-risk relapsed acute lymphoblastic leukemia (ALL) is poor. Here, we assessed the prognostic importance of response during induction and consolidation treatment prior to hematopoietic stem cell transplantation (HSCT) aiming to evaluate the best time to assess minimal residual disease (MRD) for intervention strategies and in future trials in high-risk ALL relapse patients. Included patients (n=125) were treated uniformly according to the ALL-REZ BFM (Berlin-Frankfurt-Münster) 2002 relapse trial (median follow-up time=4.8 years). Patients with MRD ⩾10−3 after induction treatment (76/119, 64%) or immediately preceding HSCT (19/71, 27%) had a significantly worse probability of disease-free survival 10 years after relapse treatment begin, with 26% (±6%) or 23% (±7%), respectively, compared with 58% (±8%) or 48% (±7%) for patients with MRD <10−3. Conventional intensive consolidation treatment reduced MRD to <10−3 before HSCT in 63% of patients, whereas MRD remained high or increased in the rest of this patient group. Our data support that MRD after induction treatment can be used to quantify the activity of different induction treatment strategies in phase II trials. MRD persistence at ⩾10−3 before HSCT reflects a disease highly resistant to conventional intensive chemotherapy and requiring prospective controlled investigation of new treatment strategies and drugs.

Polymorphisms in the DNA ligase IV gene might influence the risk of acute lymphoblastic leukemia in children

Polymorphisms in the DNA ligase IV gene might influence the risk of acute lymphoblastic leukemia in children