Renneville A.,Biology and Pathology Center |
Renneville A.,University of Lille Nord de France |
Renneville A.,Cancer Research Institute of Lille |
Boissel N.,University Paris Diderot |
And 22 more authors.
Leukemia | Year: 2012
Recently, DNA methyltransferase 3A (DNMT3A) mutations have been identified in acute myeloid leukemia (AML), the highest frequency being found within cytogenetically normal (CN) AML. In this study, diagnostic samples from 123 adults younger than 60 years with primary CN-AML homogeneously treated in the Acute Leukemia French Association-9801 and-9802 trials were screened for mutations in DNMT3A-conserved domains by direct sequencing. Patients were also assessed for the presence of FLT3 (fms-like tyrosine kinase receptor-3), NPM1 (nucleophosmin), CEBPA, WT1 (Wilms tumor 1), IDH1 (isocitrate dehydrogenase 1) and IDH2 mutations. Thirty-eight mutations were detected in 36 patients (29%): 36 nucleotide substitutions, mostly affecting amino-acid residue R882 and two frameshift deletions. DNMT3A mutations were significantly associated with the French-American-British subtypes M4/M5 and the presence of NPM1 mutations. In the whole cohort, DNMT3A mutated patients had a shorter event-free survival (5-year EFS: 13% vs 32%, P0.02) and overall survival (5-year OS: 23% vs 45%, P0.02) compared with DNMT3A wild-type patients. In multivariate analysis including age, white blood cell count, NPM1/FLT3-internal tandem duplication/CEBPA risk group and DNMT3A mutational status, the presence of a DNMT3A mutation remained an independent adverse prognostic factor for EFS and OS, suggesting that testing for DNMT3A mutations could help further improve risk stratification in CN-AML. © 2012 Macmillan Publishers Limited.
Fattoum J.,Lyon Sud Hospital |
Cannas G.,Lyon Sud Hospital |
Elhamri M.,Lyon Sud Hospital |
Tigaud I.,Laboratory of Cytogenetics |
And 5 more authors.
Clinical Lymphoma, Myeloma and Leukemia | Year: 2015
Abstract Background Patients aged ≥ 70 years with acute myeloid leukemia (AML) have a poorer prognosis than those aged 60 to 69 years. Patients and Methods We retrospectively analyzed the cases of 183 patients aged ≥ 70 years with a performance status of ≤ 2 treated at our institution from 2000 to 2014. Treatment consisted of anthracycline- and cytarabine-based chemotherapy for 93 patients and lower intensity therapy with low-dose cytarabine or hypomethylating agent cycles for 90 patients. Results A total of 57 patients (61%) achieved complete remission in the intensive chemotherapy group versus only 11 (12%) in the lower intensity treatment group (P <.0001). The median overall survival (OS) was 14.5 months and 11.7 months with a 3-year OS rate of 34% and 18% (P =.005) for the intensive and lower intensity groups, respectively. The difference remained significant when considering patients aged ≤ 75 years, but not for patients aged > 75 years. Similarly, a significant difference was only observed when considering favorable and intermediate cytogenetic factors (P =.007) but not unfavorable karyotypes. On multivariate analysis, age did not appear as an independent prognostic factor. Conclusion With intensive chemotherapy, the median OS significantly increased after the introduction of an improved supportive care policy compared with historical controls (14 vs. 5.4 months, with a 3-year OS rate of 33% vs. 8%). After 2006, a more "personalized" therapeutic approach tended to erase the difference in terms of OS, especially in patients aged > 75 years. © 2015 Elsevier Inc.
Sciuscio D.,University of Lausanne |
Diserens A.-C.,University of Lausanne |
Van Dommelen K.,University of Lausanne |
Van Dommelen K.,Center Hospitalier du Center du Valais |
And 9 more authors.
Clinical Cancer Research | Year: 2011
Purpose: Quantitative methylation-specific tests suggest that not all cells in a glioblastoma with detectable promoter methylation of the O6-methylguanine DNA methyltransferase (MGMT) gene carry a methylated MGMT allele. This observation may indicate cell subpopulations with distinct MGMT status, raising the question of the clinically relevant cutoff of MGMT methylation therapy. Epigenetic silencing of the MGMT gene by promoter methylation blunts repair of O6-methyl guanine and has been shown to be a predictive factor for benefit from alkylating agent therapy in glioblastoma. Experimental Design: Ten paired samples of glioblastoma and respective glioblastoma-derived spheres (GS), cultured under stem cell conditions, were analyzed for the degree and pattern of MGMT promoter methylation by methylation-specific clone sequencing, MGMT gene dosage, chromatin status, and respective effects on MGMT expression and MGMT activity. Results: In glioblastoma, MGMT-methylated alleles ranged from 10% to 90%. In contrast, methylated alleles were highly enriched (100% of clones) in respective GS, even when 2 MGMT alleles were present, with 1 exception (<50%). The CpG methylation patterns were characteristic for each glioblastoma exhibiting 25% to 90% methylated CpGs of 28 sites interrogated. Furthermore, MGMT promoter methylation was associated with a nonpermissive chromatin status in accordance with very low MGMT transcript levels and undetectable MGMT activity. Conclusions: In MGMT-methylated glioblastoma, MGMT promoter methylation is highly enriched in GS that supposedly comprise glioma-initiating cells. Thus, even a low percentage of MGMT methylation measured in a glioblastoma sample may be relevant and predict benefit from an alkylating agent therapy. ©2010 AACR.
Kontek R.,Laboratory of Cytogenetics |
Kontek B.,University of Lodz |
Grzegorczyk K.,University of Lodz
Archives of Medical Science | Year: 2013
Introduction: Cancer cells, compared to normal cells, are under increased oxidative stress associated with oncogenic transformation, alterations in metabolic activity, and increased generation of reactive oxygen species. Material and methods: We investigated the ability of vitamin C to reduce the damage induced by hydrogen peroxide, in human colorectal adenocarcinoma cells in vitro by the comet assay. Additionally, we measured the kinetics and efficacy of the repair of DNA damage after incubation with vitamin C in the presence of H2O2. Results: The obtained results showed that 1 h pre-incubation with vitamin C and exposure to H2O2 for the last 10 min of incubation caused a statistically significant (p < 0.05) increase in DNA migration in comet tails in all experimental series. For the 10 ìM, 25 μM, 50 μM, 100 μM vitamin C concentrations the levels of DNA damage were as follows: 18.6%, 21.1%, 25.3% and 27.2%, respectively, as compared to the untreated cells (3.26%). However, in comparison with H2O2 alone (29.1%), we observed a statistically significant (p < 0.05) decrease of the genotoxic effect in HT29 cells induced by H2O2 for the two lowest of concentrations of vitamin C: 10 μM and 25 μM. The HT29 cells were able to achieve effective repair of the damaged DNA within 60 and 120 min after incubation with the tested compounds. All the values obtained in the test were statistically significant (p < 0.05). Conclusions: Vitamin C caused a weaker DNA damaging effect of hydrogen peroxide and positively influences the level of oxidative DNA damage in HT29 cells (decrease ~ 30%). We noted that DNA damage was effectively repaired during 120 min postincubation in the tested cells and that oxidative damage was the major type of damage.
Sa R.,University of Porto |
Cremades N.,University of Alicante |
Malheiro I.,Laboratory of Cytogenetics |
Sousa M.,University of Porto |
Sousa M.,Center for Reproductive Genetics Alberto Barros
Andrologia | Year: 2012
For patients with threatened fertility, preservation of it is a major concern. Although promising results have been obtained in animal models using testicular germ cell suspensions, in humans, it is crucial to first develop an efficient method of cryopreservation to be able to apply to transplantation. Thus, four reliable and available cryopreservation techniques in any fertility centre were tested to cryopreserve an enriched fraction of diploid germ cells isolated from human testicular biopsies. The protocols were evaluated based on cell viability, and the results showed significant differences between the four methods. The semen and tissue cryopreservation methods appeared to be inadequate for diploid germ cell suspensions, and programmed slow freezing gave significantly lower results than open pulled straw vitrification; the latter was found to be the protocol that best preserved cell viability. The vitrification of isolated human diploid germ cells is innovative and constitutes valuable information for cryopreservation in cases of transplants or in vitro maturation. © 2012 Blackwell Verlag GmbH.