Myelodysplastic syndrome: classification and prognostic systems

Advancements in minimal residual disease detection: a practical approach using single-cell droplet PCR for comprehensive monitoring in hematological malignancy

The identification of chromosomal abnormalities accompanied by copy number alterations is important for understanding tumor characteristics. Testing methodologies for copy number abnormality have limited sensitivity, resulting in their use only for the sample provided at the time of diagnosis or recurrence of malignancy, but not for the monitoring of minimal residual disease (MRD) during and after therapy. We developped the "DimShift" technology which enable to measure the copy number of target gene/chromosome in each cell, which is given by the single cell droplet PCR. Qualitative result of DimShift given by peripheral blood was perfectly concordant with that of bone marrow. These findings and performances are promising to be the new methodology for MRD detection in malignant diseases utilizing bone marrow as well as peripheral blood.

Ring Chromosomes in Hematological Malignancies Are Associated with TP53 Gene Mutations and Characteristic Copy Number Variants

Ring chromosomes (RC) are present in <10% of patients with hematological malignancies and are associated with poor prognosis. Until now, only small cohorts of patients with hematological neoplasms and concomitant RCs have been cytogenetically characterized. Here, we performed a conventional chromosome analysis on metaphase spreads from >13,000 patients diagnosed with hematological malignancies at the Johns Hopkins University Hospital and identified 98 patients with RCs-90 with myeloid malignancies and 8 with lymphoid malignancies. We also performed a targeted Next-Generation Sequencing (NGS) assay, using a panel of 642 cancer genes, to identify whether these patients harbor relevant pathogenic variants. Cytogenetic analyses revealed that RCs and marker chromosomes of unknown origin are concurrently present in most patients by karyotyping, and 93% of patients with NGS data have complex karyotypes. A total of 72% of these individuals have pathogenic mutations in TP53, most of whom also possess cytogenetic abnormalities resulting in the loss of 17p, including the loss of TP53. All patients with a detected RC and without complex karyotypes also lack TP53 mutations but have pathogenic mutations in TET2. Further, 70% of RCs that map to a known chromosome are detected in individuals without TP53 mutations. Our data suggest that RCs in hematological malignancies may arise through different mechanisms, but ultimately promote widespread chromosomal instability.

The Differencies in Adult and Pediatric Myelodysplastic Syndrome: A Review

Myelodysplastic syndrome (MDS) represent very heterogenous group of clonal stem cell bone marrow disorders with ineffective haematopoesis leading to cytopenias in peripheral blood and increased risk of blastic transformation and evolution of acute myeloid leukemia. MDS is a disease of older age mostly, in children it seems to be very rare. There are several significant morphological, cytogenetic and prognostic differencies of the disease in adults and in children. Adult MDS patients most commonly manifest with symptoms of anemia, bleeding and infection are uncommon. In childhood, MDS manifests predominantly by neutropenia and thrombocytopenia. In addition, some pediatric MDS patients present also with constitutional disease’s signs and symptoms. Early and correct diagnosis in both age groups is essential for the choice of appropriate therapy and also for next life of patients. However, the diagnosis of MDS is challenging, complex and requiring close correlation of clinical symptoms, laboratory parameters and standardized examination of BM biopsies. The authors present an overview focused on biology of MDS in adults and children, on the differences in the incidence, clinical presentation and treatment. They summarize the possibilities and limits of histopathological diagnosis and differential diagnosis of the disease in different age groups. A major problem in the morphological diagnosis of MDS remains the determination, whether the myelodysplasia is due to clonal disorder. It might result also from some other factors, as significant dysplasia can also occur in reactive conditions, and vice versa, only discrete dysplasia is sometimes observed in MDS patients. Although histomorphological and immunohistochemical analysis of BM biopsy is invasive and time-consuming examination, it has its value in the diagnosis, differential diagnosis and evaluation of therapeutic effect.

Clinical presentation, diagnosis, and prognosis of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) comprise a group of underrecognized hematologic clonal malignancies with variable propensity for leukemic transformation that can present a diagnostic challenge because they lack hallmark symptoms. MDS can present with varying degrees of anemia, neutropenia, and thrombocytopenia, and at presentation can range from indolent to life threatening. The clinician should have a heightened level of suspicion when treating elderly patients and those with prior exposure to chemotherapy, radiation, and environmental toxins in the presence of unexplained cytopenias. Chronic anemia should not be considered a natural consequence of aging. Approximately 1 in 6 patients with unexplained anemia may have findings compatible with MDS, suggesting that MDS should be considered higher in the differential diagnosis. Primary care physicians are encouraged to conduct comprehensive evaluations to exclude non-MDS-related causes for persistent cytopenias. Patients with pancytopenia, bicytopenia, or any persistent and unexplained isolated cytopenia (and particularly unexplained macrocytic anemia) should be referred to a specialist to establish a diagnosis.

Biclonal myelodysplastic syndrome involving six chromosomes and monoallelic loss of RB1 - A rare case

Background

Myelodysplastic syndrome (MDS) represents a group of clonal hematological disorders characterized by progressive cytopenia, and reflects to defects in erythroid, myeloid and megakaryocytic maturation. MDS is more frequently observed in older aged patients with cytogenetic abnormalities like monosomy of chromosome(s) 5 and/or 7. In 50% of de novo MDS cases, chromosomal aberrations are found and rearrangements involving the retinoblastoma (RB1) gene in 13q14 are found.

Results

Here, we are presenting a case report of a rare biclonal MDS with a karyotype of 45, XY,-4, der(6)t(4;6)(p15.1;p21.3), der(8)t(4;8)(q31.2;q22), t(13;16)(q21.3;p11.2)[11]/45, XY, der(7)t(7;13)(p22.2~22.3;q21.3),-13 [9]. The patient was diagnosed according to WHO classification as refractory anemia with excess of blasts (RAEB-II).

Immunophenotyping was positive for CD11b, CD11c, CD10, CD13, CD15, CD16 and CD33.

Conclusion

We report, a novel and cytogenetically rare case of a biclonal MDS with complex chromosomal aberrations and deletion of RB1-gene in both clones. These findings are associated with a poor prognosis as the patient died 3 months after diagnosis.