Myelodysplastic syndromes, aging, and age: Correlations, common mechanisms, and clinical implications

Inherited and Somatic Defects in DDX41 in Myeloid Neoplasms

Most cases of adult myeloid neoplasms are routinely assumed to be sporadic. Here, we describe an adult familial acute myeloid leukemia (AML) syndrome caused by germline mutations in the DEAD/H-box helicase gene DDX41. DDX41 was also found to be affected by somatic mutations in sporadic cases of myeloid neoplasms as well as in a biallelic fashion in 50% of patients with germline DDX41 mutations. Moreover, corresponding deletions on 5q35.3 present in 6% of cases led to haploinsufficient DDX41 expression. DDX41 lesions caused altered pre-mRNA splicing and RNA processing. DDX41 is exemplary of other RNA helicase genes also affected by somatic mutations, suggesting that they constitute a family of tumor suppressor genes.

Circulating microRNA as Biomarkers in Hematological Malignancies

Hematopoiesis is a highly regulated process controlled by a complex network of molecular mechanisms that simultaneously regulate differentiation, proliferation, and apoptosis of hematopoietic stem cells. Aberrant microRNA (miRNA) expression could affect normal hematopoiesis, leading to the development of hematological malignancies. Hematologic cancers, which are caused by malignant transformation of cells of the bone marrow and the lymphatic system, are usually divided into three major groups: leukemias, lymphomas, and monoclonal gammopathies. Hematologic malignancies are highly aggressive diseases with high morbidity and mortality. For these reasons, early and easily obtainable markers for diagnosis, risk stratification, and follow-up are essential for improvement of outcome and survival of these patients. Recent studies have provided new insights about the diagnostic value of expression patterns of miRNAs in serum/plasma in these diseases. While the use of circulating miRNAs is only at the experimental level, it appears to have a great potential. This chapter deals with the use of circulating miRNAs as minimally invasive biomarkers in hematologic malignancies.

Impact of comorbidities by ACE-27 in the revised-IPSS for patients with myelodysplastic syndromes

Comorbidities significantly affect the prognosis and outcomes of patients with hematological malignancies. We have previously reported the impact of comorbidities on the International Prognostic Scoring System (IPSS) score. The aim of this study was to determine whether comorbidities continued to have a significant impact when patients were reclassified according to the Revised-IPSS (IPSS-R). The medical records of 600 consecutive myelodysplastic syndrome patients who presented to MD Anderson Cancer Center between January 2002 and June 2004 were reviewed. The Adult Comorbidity Evaluation-27 (ACE-27) was used to assess the severity of comorbid conditions. Four hundred and two (67%) patients were male. Median age at presentation was 66.6 years (17-94). Mean duration of follow-up was 54 months (1-100). Five hundred and two (84%) patients died, and 54 (9%) patients underwent stem cell transplantation. Overall median survival was 16.8 months (1-100). Median survival by IPSS-R was 47, 34, 21, 16, and 6 months for patients in very low, low, intermediate, high, and very high-risk groups, respectively (P < 0.001). The ACE-27 comorbidity score significantly impacted the median survival of patients in the intermediate (P < 0.001), high (P = 0.045), and very high (P = 0.004) IPSS-R groups; but did not significantly impact the median survival in the low (P = 0.11) and very low (P = 0.49) IPSS-R groups. The ACE-27 comorbidity score significantly impacted the median survival of patients ≤65 years (P < 0.001) but did not significantly impact those >65 years (P = 0.18). Assessment of comorbidity may enhance the prognostic ability of the IPSS-R.

Immune dysregulation in myelodysplastic syndrome

Myelodysplastic syndrome (MDS) represents one of the most challenging health-related problems in the elderly. Characterized by dysplastic morphology in the bone marrow in association with ineffective hematopoiesis, pathophysiological causes of this disease are diverse including genetic abnormalities within myeloid progenitors, altered epigenetics, and changes in the bone marrow microenvironment. The concept that T-cell mediated autoimmunity contributes to bone marrow failure has been widely accepted due to hematologic improvement after immunosuppressive therapy (IST) in a subset of patients. Currently, IST for MDS primarily involves anti-thymocyte globulin (ATG)-based regimens in which responsiveness is strongly associated with younger (under 60 years) age at disease onset. In such cases, progressive cytopenia may occur as a consequence of expanded self-reactive CD8⁺ cytotoxic T lymphocytes (CTLs) that suppress hematopoietic progenitors. Although most hematologists agree that IST can offer durable hematologic remission in younger patients with MDS, an international clinical study and a better understanding of the molecular mechanisms contributing to the expansion of self-reactive CTLs is crucial. In this review, data accumulated in the US, Europe, and Asia will be summarized to provide insight and direction for a multi-center international trial.

Standardization of flow cytometry in myelodysplastic syndromes: a report from an international consortium and the European LeukemiaNet Working Group

Flow cytometry (FC) is increasingly recognized as an important tool in the diagnosis and prognosis of myelodysplastic syndromes (MDS). However, validation of current assays and agreement upon the techniques are prerequisites for its widespread acceptance and application in clinical practice. Therefore, a working group was initiated (Amsterdam, 2008) to discuss and propose standards for FC in MDS. In 2009 and 2010, representatives from 23, mainly European, institutes participated in the second and third European LeukemiaNet (ELN) MDS workshops. In the present report, minimal requirements to analyze dysplasia are refined. The proposed core markers should enable a categorization of FC results in cytopenic patients as 'normal', 'suggestive of', or 'diagnostic of' MDS. An FC report should include a description of validated FC abnormalities such as aberrant marker expression on myeloid progenitors and, furthermore, dysgranulopoiesis and/or dysmonocytopoiesis, if at least two abnormalities are evidenced. The working group is dedicated to initiate further studies to establish robust diagnostic and prognostic FC panels in MDS. An ultimate goal is to refine and improve diagnosis and prognostic scoring systems. Finally, the working group stresses that FC should be part of an integrated diagnosis rather than a separate technique.

Telomere length and anaemia in old age: results from the Newcastle 85-plus Study and the Leiden 85-plus Study

BACKGROUND

reduced telomere length in blood cells has been associated with increased risk of multiple age-related diseases and is widely regarded as a general biomarker of ageing. Therefore, it is important to know both the extent and limitations of this association. We investigated the relation between telomere length and anaemia in two independent cohorts, with the prior expectation of adding anaemia to the list of conditions for which telomere reduction is a risk factor.

PARTICIPANTS AND METHODS

the present study is embedded in the Newcastle 85-plus Study and Leiden 85-plus Study, two population-based studies of inhabitants of Newcastle and North Tyneside, UK (n = 749) and Leiden, the Netherlands (n = 658) aged 85 and over. High-molecular-weight DNA was isolated from full fresh blood (Newcastle) and peripheral blood mononuclear cells samples (Leiden). Telomere length was measured as abundance of telomeric template versus a single gene by quantitative real-time polymerase chain reaction. Anaemia was defined according to World Health Organization criteria.

RESULTS

in both studies, no differences in median telomere length were observed between participants with anaemia and participants without anaemia (Newcastle: 2,846 bp (interquartile range (IQR) 2,433-3,630) versus 2,920 bp (IQR 2,425-3,570), P = 0.63; Leiden: 4,136 bp (IQR 3,879-4,428) versus 4,167 bp (IQR 3,893-4,501), P = 0.41). Telomere length also did not correlate with any other haematological parameter in both men and women.

CONCLUSIONS

in contrast to other age-related diseases, telomere length is not associated with anaemia or any other haematological parameter in older individuals in the general population.

Association of comorbidities with overall survival in myelodysplastic syndrome: development of a prognostic model

PURPOSE

Patients with cancer often experience comorbidities that may affect their prognosis and outcome. The objective of this study was to determine the effect of comorbidities on the survival of patients with myelodysplastic syndrome (MDS).

PATIENTS AND METHODS

We conducted a retrospective cohort study of 600 consecutive patients with MDS who presented to MD Anderson Cancer Center from January 2002 to December 2004. The Adult Comorbidity Evaluation-27 (ACE-27) scale was used to assess comorbidities. Data on demographics, International Prognostic Scoring System (IPSS), treatment, and outcome (leukemic transformation and survival) were collected. Kaplan-Meier methods and Cox regression were used to assess survival. A prognostic model incorporating baseline comorbidities with age and IPSS was developed to predict survival.

RESULTS

Overall median survival was 18.6 months. According to the ACE-27 categories, median survival was 31.8, 16.8, 15.2, and 9.7 months for those with none, mild, moderate, and severe comorbidities, respectively (P < .001). Adjusted hazard ratios were 1.3, 1.6, and 2.3 for mild, moderate, and severe comorbidities, respectively, compared with no comorbidities (P < .001). A final prognostic model including age, IPSS, and comorbidity score predicted median survival of 43.0, 23.0, and 9.0 months for lower-, intermediate-, and high-risk groups, respectively (P < .001).

CONCLUSION

Comorbidities have a significant impact on the survival of patients with MDS. Patients with severe comorbidity had a 50% decrease in survival, independent of age and IPSS risk group. A comprehensive assessment of the severity of comorbidities helps predict survival in patients with MDS.

Hematopoiesis-related microRNA expression in myelodysplastic syndromes

MicroRNAs (miRNAs) are negative regulators of expression of genes involved in hematopoiesis. The present study sought to link hematopoiesis-relevant miRNAs with myelodysplastic syndromes (MDS) and MDS progression to acute myeloid leukemia (AML). We assessed 25 mature miRNAs in total RNA from bone marrow (BM) and peripheral blood (PB) of 25 newly diagnosed patients with MDS and 12 controls. Twelve miRNAs in BM and six in PB were differentially expressed between patients with MDS and controls. Three of these miRNAs, belonging to the cluster 17-92, were overexpressed in both BM and PB. miR-15a in BM ( p = 0.034) and miR-16 in PB ( p = 0.005) were differentially expressed between low-risk and high-risk groups. miR-222 ( p = 0.0023) and miR-181a ( p = 0.014) expression was higher in AML than in MDS in both BM and PB. This study adds further evidence to the role of miRNAs in the pathogenesis of MDS and their transformation into AML.

Phosphoinositide-Phospholipase C β1 Mono-Allelic Deletion Is Associated With Myelodysplastic Syndromes Evolution Into Acute Myeloid Leukemia

Purpose

To evaluate the association between the presence of phosphoinositide-phospholipase C β1 (PI-PLCβ1) mono-allelic deletion with the clinical outcome of myelodysplastic syndromes (MDS) patients.

Methods

PI-PLCβ1, PI-PLCβ4, and PI-PLCγ1 cytogenetic investigations were performed on 80 newly diagnosed MDS patients (18 low risk, 26 intermediate 1, 18 intermediate 2, 18 high risk) comparing the results with the clinical outcome of the patients. Moreover, fluorescent in situ hybridization results were validated by real-time polymerase chain reaction (PCR). Finally, PI-PLCβ1 gene and protein expression were assessed by both real-time PCR and immunocytochemical experiments.

Results

Collectively, 35 (43.75%) of 80 of the MDS patients showed a specific mono-allelic deletion of PI-PLCβ1. Kaplan-Meier analysis revealed a significant association (P < .0001) between the PI-PLCβ1 mono-allelic deletion and a higher risk of evolution into acute myeloid leukemia (AML), since 23 of 35 MDS patients (65.7%) bearing the PI-PLCβ1 mono-allelic deletion evolved into AML. Even in multivariate analysis, the PI-PLCβ1 mono-allelic deletion retained a higher significance, with a P < .001, as a prognostic factor of evolution into AML (odds ratio [OR] 1.83; 95% CI, 2.26 to 17.24; P = .00045). Finally, PI-PLCβ1 deletion was related to an altered gene and protein expression.

Conclusion

PI-PLCβ1 mono-allelic deletion is associated with a worse clinical outcome in MDS patients, hinting at the identification of a new group at higher risk of AML evolution and representing a reliable prognostic tool. Moreover, targeting PI-PLCβ1 pathways might emerge as a new therapeutic strategy for MDS.