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Purpose To determine whether minimal residual disease (MRD) measured by Wilms' tumor gene 1 (WT1) expression is a prognostic marker in pediatric acute myeloid leukemia (AML), we quantified WT1 transcript by real-time quantitative-polymerase chain reaction in 92 AML at diagnosis and during follow-up. Patients and Methods Patients (median age, 6 years; cytogenetics, favorable 27%, intermediate 59%, poor 13%) were treated between 1995 and 2002 and enrolled in Leucémie aiguë Myéloblastique Enfant (LAME) 89/91, LAME 99 pilot study and Acute Promyelocytic Leukemia French collaborative protocols. With a median follow-up of 26 months, event-free survival was 56% with a standard deviation (SD) of 5% and overall survival of 62.5% with an SD of 6%. WT1 copy number was normalized by TATA box binding protein gene transcripts and expressed as WT1/TBP × 1,000 ratio. Median WT1 ratio in normal patient controls was 12 (range, 0 to 57). A level over two SD than normal bone marrow controls (ie, WT1 ratio > 50), was considered as significant overexpression. Results At diagnosis, WT1 overexpression was detected in 78% of patients (72 of 92 patients; median copy ratio, 2231). The WT1 values were significantly higher (P = .01) in favorable cytogenetics and lower (P < .0001) in M5-FAB subtype, 11q23 rearrangements (P < .001), and infants (P = .003) and demonstrate a strong correlation with fusion transcript AML1-ETO, PML-RARα expression. After induction treatment, WT1 ratio was analyzed in 46 of 72 patients and found above 50 in nine of 36 patients and five of 25 patients at D35-50 and 3 to 5 months, respectively. WT1 ratio > 50 after induction is an independent prognostic risk factor of relapse (P = .002) and death (P = .02). Conclusion WT1 quantification is an informative molecular marker for MRD in pediatric AML and is now performed as prospective analysis in ELAM02 protocol.

PURPOSE To analyze retrospectively survival and prognostic factors of patients with non-Hodgkin's lymphoma (NHL) autografted from 1979 to 1995 in a single institution. PATIENTS AND METHODS A total of 120 patients, 64 with aggressive and 56 with low-grade NHL, were autografted. The carmustine (BCNU), etoposide, cytarabine, and melphalan (BEAM) regimen was used in 104. The autograft was marrow in 101 patients. Marrow was purged in vitro by mafosfamide for 63 patients (adjusted dose [AD] in 32; unique dose [UD] in 31); 27 patients received a CD34+-selected graft. Following intensification, 45 patients received additional radiotherapy on previous sites of involvement. RESULTS Outcome at 5 years for patients transplanted with low-grade NHL in first complete remission (CR1), in first partial remission (PR1), and in second complete remission (CR2) or beyond showed an event-free survival (EFS) of 75% +/- 12%, 46% +/- 18%, and 57% +/- 24%, a relapse incidence (RI) of 21% +/- 12%, 49% +/- 19%, and 43% +/- 25%, and a transplant-related mortality (TRM) of 5% +/- 5%, 10% +/- 7%, and 0%, respectively. For patients with aggressive NHL transplanted in CR1, in PR1, in CR2 or beyond, and in resistant relapse or in primary refractory disease, the EFS was of 73% +/- 9%, 58% +/- 19%, 29% +/- 16%, and 10% +/- 9%, the RI 22% +/- 9%, 14% +/- 9%, 77% +/- 18%, and 66% +/- 20%, and the TRM 6% +/- 6%, 32% +/- 21%, 11% +/- 10%, and 71% +/- 22%, respectively. In patients autografted upfront in first remission, additional radiotherapy was associated with a higher EFS, in univariate (P = .03) and multivariate analysis (P = .02, relative risk [RR] = .021). The role of graft purging with mafosfamide on the outcome reflected by the dose of colony-forming unit-granulocyte-macrophage (CFU-GM) per kilogram infused postpurging was assessed by univariate analysis: patients in first remission who received lower doses of CFU-GM had a lower RI and a higher EFS. CONCLUSION This retrospective analysis suggests that marrow purging and posttransplant radiotherapy improve the outcome of patients with NHL autografted in first remission.