Fabiola Fernandes Heredia

Polymorphisms of DNA repair genes are related to the pathogenesis of myelodysplastic syndrome

Some studies show that alterations in DNA repair genes polymorphisms are associated with the pathogenesis and susceptibility of Myelodysplastic Syndrome (MDS). We genotyped 60 MDS patients for six DNA repair gene polymorphisms: BRCA1 rs4793191, BRCA2 rs9567623, RAD51 rs1801320, XRCC5 rs3835, XRCC6 rs2267437 and LIG4 rs1805388. The G/C heterozygote genotype of rs1801320 polymorphism was associated with a decreased chance of developing MDS (p = 0.05). Additionally, the G/G homozygous genotype was associated with the presence of one cytopenia in whole blood. The genotype C/G and CG + GG of the rs2267437 polymorphism was associated with normal karyotype (p = 0.010) and bone marrow cellularity normocellular + hypercellular (p = 0.023). We found that the A/G heterozygous genotype of the rs3835 polymorphism is associated with decreased chance of developing MDS (p < 0.001). These results support the importance of RAD51, XRCC5 and XRCC6 genes polymorphisms in the maintenance of genomic stability promoting a better understanding of the genesis and etiology of MDS. Copyright

Proteins related to the spindle and checkpoint mitotic emphasize the different pathogenesis of hypoplastic MDS

Some studies show that alterations in expression of proteins related to mitotic spindle (AURORAS KINASE A and B) and mitotic checkpoint (CDC20 and MAD2L1) are involved in chromosomal instability and tumor progression in various solid and hematologic malignancies. This study aimed to evaluate these genes in MDS patients. The cytogenetics analysis was carried out by G-banding, AURKA and AURKB amplification was performed using FISH, and AURKA, AURKB, CDC20 and MAD2L1 gene expression was performed by qRT-PCR in 61 samples of bone marrow from MDS patients. AURKA gene amplification was observed in 10% of the cases, which also showed higher expression levels than the control group (p=0.038). Patients with normo/hypercellular BM presented significantly higher expression levels than hypocellular BM patients, but normo and hypercellular BM groups did not differ. After logistic regression analysis, our results showed that HIGH expression levels were associated with increased risk of developing normo/hypercellular MDS. It also indicated that age is associated with AURKA, CDC20 and MAD2L1 HIGH expression levels. The distinct expression of hypocellular patients emphasizes the prognostic importance of cellularity to MDS. The amplification/high expression of AURKA suggests that the increased expression of this gene may be related to the pathogenesis of disease.

HFE gene mutation and oxidative damage biomarkers in patients with myelodysplastic syndromes and its relation to transfusional iron overload: an observational cross-sectional study

Objective A relation between transfusional IOL (iron overload), HFE status and oxidative damage was evaluated. Design, setting and participants An observational cross-sectional study involving 87 healthy individuals and 78 patients with myelodysplastic syndromes (MDS) with and without IOL, seen at University Hospital of the Federal University of Ceará, Brazil, between May 2010 and September 2011. Methods IOL was defined using repeated measures of serum ferritin ≥1000 ng/mL. Variations in the HFE gene were investigated using PCR/restriction fragment length polymorphism (RFLP). The biomarkers of oxidative stress (plasmatic malonaldehyde (MDA), glutathione peroxidase (GPx) and superoxide dismutase (SOD)) were determined by spectrophotometry. Results The HFE gene variations were identified in 24 patients (30.77%) and 5 volunteers (5.74%). The H63D variant was observed in 35% and the C282Y variant as heterozygous in 5% of patients with MDS with IOL. One patient showed double heterozygous variant (C282Y/H63D) and serum ferritin of 11 649 ng/mL. In patients without IOL, the H63D variant was detected in 29.34%. Serum MDA levels were highest in patients with MDS with IOL, with a significant difference when compared with patients without IOL and healthy volunteers, pointing to the relationship between IOL and oxidative stress. The GPx and SOD were also significantly higher in these patients, indicating that lipid peroxidation increase was followed by an increase in antioxidant capacity. Higher ferritin levels were observed in patients with HFE gene variation. 95.7% of patients with MDS with the presence of HFE gene variations had received more of 20 transfusions. Conclusions We observed a significant increase in MDA levels in patients with MDS and IOL, suggesting an increased lipid peroxidation in these patients. The accumulation of MDA alters the organisation of membrane phospholipids, contributing to the process of cellular degeneration. Results show that excess iron intensifies the process of cell damage through oxidative stress. Trial registration number Local Ethics Committee (licence 150/2009).

Proteins of the mitotic checkpoint and spindle are related to chromosomal instability and unfavourable prognosis in patients with myelodysplastic syndrome

Aims To study the immunoexpression of proteins related to the mitotic checkpoint (cell division cycle 20 (CDC20), mitotic arrest deficient 2 (MAD2)) and the mitotic spindle (Aurora-B) in patients with myelodysplastic syndrome (MDS). Methods Protein expression was analysed in bone marrow tissue samples from 40 patients with MDS using immunohistochemistry. Prognostic markers (transfusion dependency, depth of cytopenias, chromosomal abnormalities and survival) were also studied. Results Higher MAD2 expression was observed among patients with platelets <50×109/L than among patients with platelets ≥50×109/L (42.6±22.8% vs 22.7±19.1%, respectively). Higher CDC20 expression was identified among patients with three dysplasias compared with patients who presented with one or two dysplasias (33.9±24.1% vs 10.5±5.7% vs 12.8±7.8%, respectively), among patients who exhibited a complex versus non-complex karyotype (50.0±30.2% vs 18.4±14%, respectively) and among patients with platelets <50×109/L vs platelets ≥50×109/L (38.2±26.2% vs 16.1±12.4%, respectively). Higher Aurora-B expression was found in patients with an abnormal versus normal karyotype (21.2±13.2% vs 7.5±5.0%, respectively). High expression of MAD2 and CDC20 (≥50%) was associated with severe thrombocytopenia. We also found statistically significant differences in the overall survival rate when comparing different degrees of CDC20, MAD2 and Aurora-B protein expression. Conclusions To the best of our knowledge, this is the first report to demonstrate that these proteins are associated with chromosomal abnormalities and poor prognosis in patients with MDS.

Aurora-B expression may not contribute to disease progression: a reflection of the heterogeneous pathogenesis?

We read with great interest the paper by Yoshida et al . entitled “Marked upregulation of survivin and Aurora-B kinase are associated with disease progression in the myelodysplastic syndromes”.[1][1] Aurora kinases are key players in ensuring accurate chromosome segregation during the cell

Therapy-related myelodysplastic syndrome with 17p deletion following long-term azathioprine treatment

Therapy-related myelodysplastic syndrome (t-MDS) is a wellecognized clinical syndrome occurring as a late complication fter cytotoxic therapy. The period between primary diagnosis and herapy-related disease ranges between few months to several ears, and it may be dependent on the ability of leukemogenic drugs o inflict DNA damage, cumulative dose or dose intensity of the receding cytotoxic therapy [1,2]. Azathioprine (AZA) is an antimetabolite drug widely used n patients with non-life threatening inflammatory and various utoimmune disorders [3–5] and after organ allografting. Incororation of deoxy-6-thioguanosine 5′triphosphate (dGS) into DNA nderlies the cytotoxicity and therapeutic effect of azathioprine, riggering cell-cycle arrest and apoptosis by a process that involves he mismatch repair (MMR) pathway [5]. AZA has been shown to nduce defective DNA-mismatch repair [1] and the expansion of an MR-deficient clone may represent an early step in the developent of t-MDS. Knipp et al. reported 14 cases of t-MDS following treatment ith AZA [6]. The great majority of cases presented abnormality f chromosome 7 (del(7q) or −7) and, of utmost importance, seven atients evolved into acute myeloid leukemia, demonstrating the oor prognosis of this disease. Loss of all or part of chromosome 7 nd 5 are frequently noted in MDS secondary to alkylating agents 4]. Thiopurines and alkylating agents differ in their structures and echanisms of action, but they share the ability to produce DNA amage that interacts with MMR [4].