The imbalance between reactive oxygen species (ROS) production and their elimination by antioxidants leads to oxidative stress. Depending on their concentration, ROS can trigger apoptosis or stimulate cell proliferation. We hypothesized that oxidative stress and mitochondrial dysfunction may participate not only in apoptosis detected in some myelodysplastic syndrome (MDS) patients, but also in increasing proliferation in other patients. We investigated the involvement of oxidative stress and mitochondrial dysfunction in MDS pathogenesis, as well as assessed their diagnostic and prognostic values. Intracellular peroxides, superoxide, superoxide/peroxides ratio, reduced glutathione (GSH), and mitochondrial membrane potential (Δψ(mit)) levels were analyzed in bone marrow cells from 27 MDS patients and 12 controls, by flow cytometry. We observed that all bone marrow cell types from MDS patients had increased intracellular peroxide levels and decreased GSH content, compared with control cells. Moreover, oxidative stress levels were MDS subtype- and risk group-dependent. Low-risk patients had the highest ROS levels, which can be related with their high apoptosis; and intermediate-2-risk patients had high Δψ(mit) that may be associated with their proliferative potential. GSH levels were negatively correlated with transfusion dependency, and peroxide levels were positively correlated with serum ferritin level. GSH content proved to be an accurate parameter to discriminate patients from controls. Finally, patients with high ROS or low GSH levels, as well as high superoxide/peroxides ratio had lower overall survival. Our results suggest that oxidative stress and mitochondrial dysfunction are involved in MDS development, and that oxidative stress parameters may constitute novel diagnosis and/or prognosis biomarkers for MDS.

Chronic antigen-stimulation has been recurrently involved in the earlier stages of monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The expansion of two or more B-cell clones has frequently been reported in individuals with these conditions; potentially, such coexisting clones have a greater probability of interaction with common immunological determinants. Here, we analyzed the B-cell receptor repertoire and molecular profile, as well as the phenotypic, cytogenetic and hematologic features, of 228 chronic lymphocytic leukemia-like and non-chronic lymphocytic leukemia-like clones comparing multiclonal (n=85 clones from 41 cases) versus monoclonal (n=143 clones) monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The B-cell receptor of B-cell clones from multiclonal cases showed a slightly higher degree of HCDR3 homology than B-cell clones from mono clonal cases, in association with unique hematologic (e.g. lower B-lymphocyte counts) and cytogenetic (e.g. lower frequency of cytogenetically altered clones) features usually related to earlier stages of the disease. Moreover, a subgroup of coexisting B-cell clones from individual multiclonal cases which were found to be phylogenetically related showed unique molecular and cytogenetic features: they more frequently shared IGHV3 gene usage, shorter HCDR3 sequences with a greater proportion of IGHV mutations and del(13q14.3), than other unrelated B-cell clones. These results would support the antigen-driven nature of such multiclonal B-cell expansions, with potential involvement of multiple antigens/epitopes. Molecular and cytogenetic characterization of expanded B-cell clones from multiclonal versus monoclonal B-cell chronic lymphoproliferative disorders ABSTRACTto clinical MBL (MBL hi ) and CLL. 13,14,18,19 If this hypothesis holds true, specific antigenic determinants could potentially be more frequently shared between the coexisting B-cell clones of multiclonal cases than between the expanded B cells in different monoclonal MBL and B-CLPD patients, due to a higher probability of interaction with common immunological determinants. This might even be true when the coexisting clones display clearly distinct immunophenotypic and cytogenetic, as well as clinical, features. [20][21][22] In order to test this hypothesis, in the present study we compared the B-cell receptor (BCR) repertoire and molecular profile, as well as the phenotypic, cytogenetic and hematologic features of CLL-like and non-CLL-like clones (n=228) from multiclonal (n=41 cases) versus monoclonal cases [n=143, including both CLL and CLL-like MBL (n=128), as well as cases of B-CLPD other than CLL and non-CLL-like MBL (n=15)]. Methods Patients and samplesA total of 184 subjects with one (n=143 monoclonal cases) or two or more (n=41 multiclonal cases) CLL/non-CLL B-CLPD (n=140) and/or CLL-like/non-CLL-like MBL (n=88) B-cell clones, as defined by the World Health Organ...

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Oxidative stress and abnormal DNA methylation have been implicated in some types of cancer, namely in myelodysplastic syndromes (MDS). Since both mechanisms are observed in MDS patients, we analyzed the correlation of intracellular levels of peroxides, superoxide anion, and glutathione (GSH), as well as ratios of peroxides/GSH and superoxide/GSH, with the methylation status of P15 and P16 gene promoters in bone marrow leukocytes from MDS patients. Compared to controls, these patients had lower GSH content, higher peroxide levels, peroxides/GSH and superoxide/GSH ratios, as well as higher methylation frequency of P15 and P16 gene promoters. Moreover, patients with methylated P15 gene had higher oxidative stress levels than patients without methylation (peroxides: 460 ± 42 MIF vs 229 ± 25 MIF, p = 0.001; superoxide: 383 ± 48 MIF vs 243 ± 17 MIF, p = 0.022; peroxides/GSH: 2.50 ± 0.08 vs 1.04 ± 0.34, p < 0.001; superoxide/GSH: 1.76 ± 0.21 vs 1.31 ± 0.10, p = 0.007). Patients with methylated P16 and at least one methylated gene had higher peroxide levels as well as peroxides/GSH ratio than patients without methylation. Interestingly, oxidative stress levels allow the discrimination of patients without methylation from ones with methylated P15, methylated P16, or at least one methylated (P15 or P16) promoter. Taken together, these findings support the hypothesis that oxidative stress is correlated with P15 and P16 hypermethylation.

Azacitidine (AZA) prolonged overall survival (OS) in the AZA-AML-001 trial. However, few subjects were randomized to AZA or intensive chemotherapy (IC). The Medical Research Council (MRC) and the Leukemia Research Foundation (LRF) developed a score for older AML patients receiving IC or non-intensive regimens, whereas the E-ALMA study validated a score for survival and response in elderly patients receiving AZA in daily practice. Both identified three groups with different risk estimates. This analysis evaluates the efficacy of frontline AZA in older AML patients (N = 710) unfit for IC from different national registries (E-ALMA + series) stratified by the MRC/LRF risk score. Median OS of patients categorized as good, standard and poor-risk groups by the MRC/LRF score was 13.4 (95% CI, 10.8-16), 12.4 (95% CI, 9.9-14.8), and 8.1 months (95% CI, 7-9.1), respectively (p = .0001). In conclusion, this is the largest retrospective cohort of older AML patients treated with AZA.

Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) share common features: elevated oxidative stress, DNA repair deficiency, and aberrant DNA methylation. We performed a hospital-based case-control study to evaluate the association in variants of genes involved in oxidative stress, folate metabolism, DNA repair, and DNA methylation with susceptibility and prognosis of these malignancies. To that end, 16 SNPs (one per gene: CAT, CYBA, DNMT1, DNMT3A, DNMT3B, GPX1, KEAP1, MPO, MTRR, NEIL1, NFE2F2, OGG1, SLC19A1, SOD1, SOD2, and XRCC1) were genotyped in 191 patients (101 MDS and 90 AML) and 261 controls. We also measured oxidative stress (reactive oxygen species/total antioxidant status ratio), DNA damage (8-hydroxy-2'-deoxyguanosine), and DNA methylation (5-methylcytosine) in 50 subjects (40 MDS and 10 controls). Results showed that five genes (GPX1, NEIL1, NFE2L2, OGG1, and SOD2) were associated with MDS, two (DNMT3B and SLC19A1) with AML, and two (CYBA and DNMT1) with both diseases. We observed a correlation of CYBA TT, GPX1 TT, and SOD2 CC genotypes with increased oxidative stress levels, as well as NEIL1 TT and OGG1 GG genotypes with higher DNA damage. The 5-methylcytosine levels were negatively associated with DNMT1 CC, DNMT3A CC, and MTRR AA genotypes, and positively with DNMT3B CC genotype. Furthermore, DNMT3A, MTRR, NEIL1, and OGG1 variants modulated AML transformation in MDS patients. Additionally, DNMT3A, OGG1, GPX1, and KEAP1 variants influenced survival of MDS and AML patients. Altogether, data suggest that genetic variability influence predisposition and prognosis of MDS and AML patients, as well AML transformation rate in MDS patients. © 2016 Wiley Periodicals, Inc.

The current study supports a relevant role for p15, p16, and DAPK hypermethylation in the genesis of the plasma cell neoplasm. DAPK hypermethylation also might be an important step in the progression from MGUS to MM.

BackgroundDespite bone marrow (BM) immunophenotyping by flow cytometry has progressively been recognized as an important tool for the diagnosis of myelodysplastic syndromes (MDS), the sparse knowledge about normal erythroid maturation and the lack of markers for erythroid characterization is a major shortcoming.MethodsHere, we analyzed the expression of CD43 and CD49d, two markers included in the diagnostic panel for B‐cell chronic lymphoproliferative disorders (B‐CLPD), in the CD34+ compartment of normal BM and along the normal and dysplastic erythroid maturation. For this, 13 normal BM aspirates and 18 BM aspirates from MDS patients were studied by flow cytometry.ResultsNormal BM presented a higher expression of CD43 and CD49d among CD34+ erythroid precursors, compared to CD34+ cells committed to the remaining hematopoietic cell lineages. CD43 expression progressively decreased along the normal erythroid maturation, whereas CD49d levels increased from Stage I to Stage II, were maintained in Stages II and III, and then decreased until the last stage of maturation. In MDS, the expression of CD43 and CD49d followed a similar pattern, but with decreased expression levels for both markers, observed in all erythroid maturation stages (P < 0.05).ConclusionsOur results point to the usefulness of CD43 and CD49d, two markers commonly present in B‐CLPD diagnosis panels, in the identification of dysplastic phenotypic features in the erythroid lineage. This allows a feasible and inexpensive way to identify patients who would benefit from a more extensive study to evaluate the presence of MDS, during the processing of suspected B‐CLPD samples. © 2019 International Clinical Cytometry Society