Background: Deletions of the 9p21 chromosomal region which encompasses CDKN2A, a gene encoding both p16INK4a and p14ARF, are frequent in childhood acute lymphoblastic leukemia (ALL). Their prognostic ...relevance is controversial. Indeed, small retrospective series of patients were analysed so far, which usually mixed B- and T-lineage ALL. Moreover, the prognosis could vary according to the extent of the deletion since the inactivation of contiguous genes such as CDKN2B encoding p15INK4b or MTAP encoding methylthioadenosine phosphorylase, may influence chemosensitivity.
Methods: 9p21 deletions were retrospectivelly studied in 227 children (aged 2 mo to 16 yrs) with B-lineage ALL, using a real-time PCR assay for CDKN2B, CDKN2A (e1b and e3), and MTAP gene dosage, and loss of heterozygosity analysis (Bertin et al., 2003). CDKN2A and CDKN2B inactivation by promoter methylation was also investigated. TEL-AML1 fusion was screened in 182 (80%) of these patients. All patients were enrolled in EORTC trials 58 881 or 58 951. Median follow-up was 6 years; total number of events was 55 and the overall 6-year EFS rate was 74%.
Results:CDKN2A bi- and mono-allelic inactivation was found in 38 (17%), and 31 (14%) B-lineage ALL respectively. Patients with a bi-allelic inactivation did not differ from undeleted ones regarding age, sex, immunophenotype and response to prephase treatment, but tended to have a higher WBC count at diagnosis and were more often allocated to the NCI high risk group (42% vs 27%). Genetic defects, including TEL-AML1, were independent of 9p21 alteration with exception of hyperdiploidy (>50 chromosomes) which was less frequent in patients with CDKN2A inactivation (5% vs 34%). The 6-year EFS rates of patients with bi-allelic, mono allelic and no inactivation did not differ significantly (68%, 80%, and 75% respectively). Bi-allelic CDKN2B inactivation by either deletion or promoter methylation was found in 36 (16%) patients and the 6-year EFS rate of these patients was similar to that of undeleted patients (71% vs 74%). MTAP bi-allelic inactivation was found in 24 (11%) of patients. Although MTAP deficient cells are in vitro very sensitive to methotrexate, the 6-year EFS rate (70% vs 75%) did not differ from that of MTAP positive patients even when the analysis was restricted to CDKN2A inactivated ALL.
Conclusion: Although bi-alleic CDKN2A inactivation was more often associated with bad prognostic parameters in B-lineage ALL, it failed to significantly influence the outcome of the patients. We did not observe either any influence of the co-inactivation of CDKN2B and MTAP on the outcome. Considering that our study is the largest so far using molecular analysis of the 9p21 region, we assume that any bad prognosis associated with 9p21 alteration, if present, should be weak in B-lineage ALL, and would probably require larger cohorts of patients to be ascertained.
Since we had previously demonstrated encouraging efficacy of etoposide in patients with relapsed or refractory Wilms' tumor (WT), the likely synergism between etoposide and platinum compounds ...prompted us to conduct a phase II study of a combination with carboplatin.
Twenty-six relapsed or refractory WT patients were included in a phase II study of two courses of combination etoposide 100 mg/m2/d for 5 days and carboplatin 160 mg/m2/d for 5 days, with a 21-day interval between the two courses. Initial stages were I (n = 2), II (n = 8), III (n = 6), IV (n = 6), V (n = 3), and unknown (n = 1). Sites of diseases were lung(s) (11 patients), abdomen-pelvis or liver or primary tumor (six patients), and multiple (eight patients). Histology was unfavorable in three of 26 patients.
Complete response (CR) was documented in eight patients and partial remission (PR) in 11 (overall response rate, 73%). Stable disease (SD) was observed in five patients and progressive disease (PD) in two. Thrombocytopenia (grade IV) was the major toxicity, and platelet transfusions were required in all but two patients. Grade III anemia and grade III to IV neutropenia were seen in 19 and 23, respectively, of 25 assessable first courses. Venoocclusive disease of the liver was fatal in one child who had undergone irradiation to the whole abdomen, 8 weeks before study.
Combination etoposide and carboplatin has impressive activity in refractory or relapsed WT at the cost of high-grade hematologic toxicity, especially thrombocytopenia. It is of great interest in second-line therapy, since eight of 26 patients are still alive in continuous CR (median follow-up duration, 40 months; range, 24 to 56). This combination deserves further investigation as first-line or consolidation treatment.
The incidence of leukemia is examined in young people (aged under 25 years) living within a 35 km radius of the French nuclear-waste reprocessing plant operating in La Hague, Normandy. During the ...period 1978-90, a total of 23 cases was diagnosed, giving an incidence rate of 2.99 per 100,000 which is close to the expected rate. In the 'canton' in which the nuclear plant is located, three cases of leukemia were observed compared with 1.2 expected, giving a standardized incidence ratio of 2.5. This nonsignificant finding is compatible with no increased risk and also with a sevenfold excess risk. Therefore, it reinforces the necessity of conducting a case-control survey, which is now planned, to assess the part played by occupational radiation exposure in leukemia incidence for this French area.
The objective of this study was to evaluate the feasibility, the toxicity and the efficiency of a BFM-like treatment protocol for acute nonlymphoblastic leukemia (ANLL) of children in which ...mitoxantrone was substituted for conventional anthracycline. The chemotherapy called for induction (mitoxantrone, cytosine arabinoside, etoposide), consolidation (mitoxantrone, cytosine arabinoside, 6 thioguanine), followed by two intensification courses with cytosine arabinoside plus, respectively, mitoxantrone during the first and etoposide during the second courses. Maintenance therapy consisted of daily 6 thioguanine, four-weekly courses of cytosine arabinoside (s.c. daily during 4 days) and eight-weekly courses of mitoxantrone. The latter drug was pursued up to a total cumulative dose of 150 mg/sqm. Maintenance therapy was stopped at 2 years of diagnosis. Out of 108 patients, 84 (77%) achieved a complete remission, 10 died during induction of hemorrhage, sepsis or pulmonary infiltration by leukemic cells. A total of 32 relapses occurred. The median follow-up was 3.5 years. Actuarial event-free survival, disease-free survival and overall survival at 3 years as 41%, 52%, 56%, respectively. These results compare favorably with most reported data, and cytogenetic findings appear to be the most important prognostic factor.
A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental ...context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems.
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