Short telomere length and its correlation with gene mutations in myelodysplastic syndrome

Telomere biology: from disorders to hematological diseases

Variations in the length of telomeres and pathogenic variants involved in telomere length maintenance have been correlated with several human diseases. Recent breakthroughs in telomere biology knowledge have contributed to the identification of illnesses named "telomeropathies" and revealed an association between telomere length and disease outcome. This review emphasizes the biology and physiology aspects of telomeres and describes prototype diseases in which telomeres are implicated in their pathophysiology. We also provide information on the role of telomeres in hematological diseases ranging from bone marrow failure syndromes to acute and chronic leukemias.

Usefulness of Genetic Aberration and Shorter Telomere Length in Myelodysplastic Syndrome: A Pilot Study

OBJECTIVE

We aimed to evaluate the clinical usefulness of genetic aberration and shorter telomere length (TL) in individuals with myelodysplastic syndrome (MDS).

METHODS

A targeted sequencing panel with 49 genes and TL measurement by quantitative real-time polymerase chain reaction were performed for 46 subjects.

RESULTS

According to the revised International Prognostic Scoring System (IPSS-R) subtypes, the mutation frequency was 33.3%, 57.9%, and 100% in the very low/low, intermediate, and very high/high risk groups, respectively. A shorter telomere was detected in 43.5%. We defined group 1 as IPSS-R-high or -very high risk, group 2 as having 1 or more genetic aberrations, group 3 as having a shorter TL, and group 4 as having a longer TL than the age-matched reference. Group 1 and group 2 showed an adverse prognosis. The TL was not strongly correlated with MDS prognosis. However, it may be related to a poor long-term prognosis.

CONCLUSION

Genetic variation and shorter TL may be helpful in reclassifying non-high-risk groups.

Analysis of clinical and genomic profiles of therapy-related myeloid neoplasm in Korea

BACKGROUND

Therapy-related myeloid neoplasm (T-MN) rarely occurs among cancer survivors, and was characterized by poor prognosis. T-MN has germline predisposition in a considerable proportion. Here, clinical characteristics and germline/somatic variant profiles in T-MN patients were investigated, and the findings were compared with those of previous studies.

METHODS

A review of medical records, cytogenetic study, targeted sequencing by next-generation sequencing, and survival analysis were performed on 53 patients with T-MN at a single institution in Korea.

RESULTS

The patients were relatively younger compared to T-MN patients in other studies. Our T-MN patients showed a high frequency of complex karyotypes, -5/del(5q), and -7/del(7q), which was similar to the Japanese study group but higher than the Australian study group. The most common primary disease was non-Hodgkin lymphoma, followed by breast cancer. The detailed distributions of primary diseases were different across study groups. Seven patients (13.2%) harbored deleterious presumed/potential germline variants in cancer predisposition genes (CPG) such as BRIP1, CEBPA, DDX41, FANCM, NBN, NF1, and RUNX1. In the somatic variant profile, TP53 was the most frequently mutated gene, which was consistent with the previous studies about T-MN. However, the somatic variant frequency in our study group was lower than in other studies. Adverse factors for overall survival were male sex, older age, history of previous radiotherapy, previous longer cytotoxic therapy, and -5/del(5q).

CONCLUSION

The findings of our study corroborate important information about T-MN patients. As well as a considerable predisposition to CPG, the clinical characteristics and somatic variant profile showed distinctive patterns. Germline variant testing should be recommended for T-MN patients. If the T-MN patients harbor pathogenic germline variants, the family members for stem cell donation should be screened for carrier status through germline variant testing to avoid donor-derived myeloid neoplasm. For the prediction of the prognosis in T-MN patients, sex, age, past treatment history, and cytogenetic findings can be considered.

Telomere integrated scoring system of myelodysplastic syndrome

INTRODUCTION

Recently, multigene target sequencing is widely performed for the purpose of prognostic prediction and application of targeted therapy. Here, we proposed a new scoring system that encompasses gene variations, telomere length, and Revised International Prognostic Scoring System (IPSS-R) together in Asian myelodysplastic syndrome.

METHODS

We developed a new scoring model of these variables: age ≥ 65 years + IPSS-R score + ASXL1 mutation + TP53 mutation + Telomere length (<5.37). According to this new scoring system, patients were divided into four groups: very good score cutoff (≤3.0), good (3.0-4.5), poor (4.5-7.0), and very poor (>7.0).

RESULTS

The median OS was 170.1, 100.4, 46.0, and 12.0 months for very good, good, poor, and very poor, retrospectively (p < 0.001). Meanwhile, according to the conventional IPSS-R scoring system, the median OS was 141.3, 50.2, 93.0, 36.0, and 16.2 months for very low, low, intermediate, high, and very high, retrospectively (p < 0.001).

CONCLUSIONS

The newly developed model incorporating molecular variations and TL yielded more clear separations of the survival curves. By adding the presence of gene mutation and telomere length to the existing IPSS-R, its predictive ability can be further improved in myelodysplastic syndrome.

The RUNX Family, a Novel Multifaceted Guardian of the Genome

The DNA repair machinery exists to protect cells from daily genetic insults by orchestrating multiple intrinsic and extrinsic factors. One such factor recently identified is the Runt-related transcription factor (RUNX) family, a group of proteins that act as a master transcriptional regulator for multiple biological functions such as embryonic development, stem cell behaviors, and oncogenesis. A significant number of studies in the past decades have delineated the involvement of RUNX proteins in DNA repair. Alterations in RUNX genes cause organ failure and predisposition to cancers, as seen in patients carrying mutations in the other well-established DNA repair genes. Herein, we review the currently existing findings and provide new insights into transcriptional and non-transcriptional multifaceted regulation of DNA repair by RUNX family proteins.

The importance of critically short telomere in myelodysplastic syndrome

A few critically short telomeres trigger genomic instability regardless of average telomere length (TL). Recently, the telomere shortest length assay (TeSLA) was developed to detect critically short telomeres and measure absolute telomeres. Using TeSLA with the internally labeled biotin probe, we measured the TL of bone marrow (BM) aspirates from 52 patients with myelodysplastic syndrome (MDS). A percentage of shortest telomeres (< 1.0 kb (ShTL1.0)) were calculated. ShTL1.0 was correlated to IPSS-R risk (spearman’s rho = 0.35 and p = 0.0196), and ShTL1.0 and BM blast (2.61% in < 5% blast, 4.15% in 5–10% blast, and 6.80% in 10–20% blast, respectively, p = 0.0332). Interestingly, MDS patients with a shortest TL ≥ 0.787 kb at the time of diagnosis showed better overall survival (OS) and progression-free survival (PFS) than patients with a shortest TL < 0.787 kb in the multivariate analyses (HR = 0.13 and 0.30, p = 0.011 and 0.048 for OS and PFS, respectively). Our results clearly show the presence and abundance of critically short telomeres in MDS patients. These pathologic telomeres are associated with IPSS-R which is a validated prognostic scoring system in MDS. Furthermore, they are independent prognostic factors for OS in MDS patients. Future prospective studies are needed to validate our results.

Telomere length (TL) has been reported to be important in myelodysplastic syndrome (MDS).A novel TeSLA method demonstrated the presence and abundance of extremely short telomeres (<1.0kb) in MDS.Critically short TL rather than an average TL is associated with the IPSS-R and BM blast in MDS.The shortest TL is an independent prognostic factor for PFS and OS.Short TL should be incorporated into the risk scoring system in MDS in the future.

The Biological and Clinical Consequences of RNA Splicing Factor U2AF1 Mutation in Myeloid Malignancies

Mutations of spliceosome genes have been frequently identified in myeloid malignancies with the large-scale application of advanced sequencing technology. U2 small nuclear RNA auxiliary factor 1 (U2AF1), an essential component of U2AF heterodimer, plays a pivotal role in the pre-mRNA splicing processes to generate functional mRNAs. Over the past few decades, the mutation landscape of U2AF1 (most frequently involved S34 and Q157 hotspots) has been drawn in multiple cancers, particularly in myeloid malignancies. As a recognized early driver of myelodysplastic syndromes (MDSs), U2AF1 mutates most frequently in MDS, followed by acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPNs). Here, for the first time, we summarize the research progress of U2AF1 mutations in myeloid malignancies, including the correlations between U2AF1 mutations with clinical and genetic characteristics, prognosis, and the leukemic transformation of patients. We also summarize the adverse effects of U2AF1 mutations on hematopoietic function, and the alterations in downstream alternative gene splicing and biological pathways, thus providing comprehensive insights into the roles of U2AF1 mutations in the myeloid malignancy pathogenesis. U2AF1 mutations are expected to be potential novel molecular markers for myeloid malignancies, especially for risk stratification, prognosis assessment, and a therapeutic target of MDS patients.

Telomere biology disorders

Telomere biology disorders (TBD) are a heterogeneous group of diseases arising from germline mutations affecting genes involved in telomere maintenance. Telomeres are DNA-protein structures at chromosome ends that maintain chromosome stability; their length affects cell replicative potential and senescence. A constellation of bone marrow failure, pulmonary fibrosis, liver cirrhosis and premature greying is suggestive, however incomplete penetrance results in highly variable manifestations, with idiopathic pulmonary fibrosis as the most common presentation. Currently, the true extent of TBD burden is unknown as there is no established diagnostic criteria and the disorder often is unrecognised and underdiagnosed. There is no gold standard for measuring telomere length and not all TBD-related mutations have been identified. There is no specific cure and the only treatment is organ transplantation, which has poor outcomes. This review summarises the current literature and discusses gaps in understanding and areas of need in managing TBD.

Oxidative Stress Is Associated with Telomere Interaction Impairment and Chromatin Condensation Defects in Spermatozoa of Infertile Males

Telomere length can be influenced by reactive oxygen species (ROS) generated by lifestyle factors or environmental exposure. We sought to determine whether oxidative stress has an impact on sperm nuclear alterations, especially on chromatin organization and telomere interactions in the spermatozoa of infertile males. We performed an observational and prospective study including fifty-two males, allocated in the "case group" (30 infertile males presenting conventional semen parameter alterations) and the "control group" (22 males with normal conventional semen parameters). ROS detection was determined on spermatozoa using CellROX^© probes. Sperm nuclear damage was assessed using quantitative fluorescence in situ hybridization (Q-FISH) for relative telomere length and telomere number, aniline blue staining for chromatin condensation, terminal deoxynucleotidyl transferase dUTP nick-end labeling for DNA fragmentation, and FISH for aneuploidy and 8-hydroxy-2'-deoxyguanosine immunostaining for oxidative DNA damages. Infertile males had significantly increased levels of cytoplasmic ROS and chromatin condensation defects as well as a higher mean number of telomere signals per spermatozoon in comparison with controls. In addition, the mean number of sperm telomere signals were positively correlated with the percentage of spermatozoa with chromatin condensation defect. In infertile males with conventional semen parameter alterations, oxidative stress is associated with telomere interaction impairment and chromatin condensation defects.

Role of Telomeres Shortening in Atherogenesis: An Overview

It is known that the shortening of the telomeres leads to cell senescence, accompanied by acquiring of pro-inflammatory phenotype. The expression of telomerase can elongate telomeres and resist the onset of senescence. The initiation of atherosclerosis is believed to be associated with local senescence of the endothelial cells of the arteries in places with either low or multidirectional oscillatory wall shear stress. The process of regeneration of the artery surface that has begun does not lead to success for several reasons. Atherosclerotic plaques are formed, which, when developed, lead to fatal consequences, which are the leading causes of death in the modern world. The pronounced age dependence of the manifestations of atherosclerosis pushes scientists to try to link the development of atherosclerosis with telomere length. The study of the role of telomere shortening in atherosclerosis is mainly limited to measuring the telomeres of blood cells, and only in rare cases (surgery or post-mortem examination) are the telomeres of local cells available for measurement. The review discusses the basic issues of cellular aging and the interpretation of telomere measurement data in atherosclerosis, as well as the prospects for the prevention and possible treatment of atherosclerosis.

Differential U2AF1 mutation sites, burden and co-mutation genes can predict prognosis in patients with myelodysplastic syndrome

To investigate the U2AF1 gene mutation site, mutation load and co-mutations genes in patients with myelodysplastic syndrome (MDS) and their effects on prognosis. Gene mutation detection by next-generation sequence and related clinical data of 234 MDS patients were retrospectively collected and analyzed for the relationship between the clinical characteristics, treatment efficacy and prognosis of U2AF1 gene mutation. Among the 234 MDS patients, the U2AF1 gene mutation rate was 21.7% (51 cases), and the median variant allele frequency was 39.5%. Compared with the wild type, the U2AF1 mutant had a higher incidence of chromosome 8 aberration, and was positively correlated with the occurrence of ASXL1, RUNX1, SETBP1 gene mutation, negatively correlated with SF3B1, NPM1 genes mutation (p < 0.05). The most common mutation site of U2AF1 was S34F (32 cases), while U2AF1 Q157P site mutations had a higher incidence of chromosome 7 abnormalities (p = 0.003). The U2AF1 gene mutation more frequently coincided with signal pathway related gene mutations (p = 0.043) with a trend of shortened overall survival. Among patients with U2AF1 gene mutations, those with ASXL1 mutations were prone to develop into acute myeloid leukemia, those with RUNX1 mutations had an increased risk of relapse, and those with TET2 mutations had higher 1-year survival rate. Compared with the patient group of lower mutation load (VAF ≤ 40%), the group with higher mutation load of U2AF1 (VAF > 40%) had a significantly lower 1-year survival rate (46.1% and 80.5%, p = 0.027). The criteria of U2AF1 VAF > 40% is an independent indicator for poor prognosis of MDS patients. VAF > 40% of U2AF1 is an independent factor of short OS in MDS patients. MDS patients with a mutation in the Q157P site of U2AF1 and a higher U2AF1 mutation load suggests poor prognosis, and co-mutated genes in U2AF1 can affect disease progression and prognosis.

Short Dysfunctional Telomere Is Highly Predictive of Dismal Outcome in MDS but Not in AML Patients

Background: A trigger for initiation the clonal hematopoietic stem cells disorders could be short telomere length probably due to chromosomal instability. The relationship between relative telomere length (RTL) and the two linked hematological stem cell disorders, myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) is still unclear.

Materials and Methods: We evaluated the role of RTL in MDS (n=96) and AML (n=130) at the time of diagnosis using a real time quantitative polymerase chain reaction (RT-PCR) technique. The median value of RTL (1) was set as the cutoff for statistical comparison. Overall survival (OS) is defined as the time from diagnosis to death or last follow-up.

Results: RTL was significantly longer in both MDS and AML cases versus control (p<0.0001) and was significantly longer in MDS versus AML cases (p =0.03). RTL correlated negatively with age in MDS (p <0.0001) but not in AML cases. RTL was also significantly shorter in MDS cases with pancytopenia and poor risk cytogenetics (p < 0.0001 for each) and short RTL was significantly associated with inferior survival (p = 0.007), while RTL showed no significant impact on OS in AML cases. Moreover, short RTL retained independent prognostic value in multivariate analysis (HR= 3.42 [95% CI, 8.97-19.35], p = 0.004).

Conclusion: RTL showed an association with both AML and MDS; however, short RTL was an independent poor prognostic factor in MDS patients only.

Prognostic significance of U2AF1 mutations in myelodysplastic syndromes: a meta-analysis

INTRODUCTION

Although the effects of U2 small nuclear RNA auxiliary factor 1 gene (U2AF1) mutations on the outcomes of patients with myelodysplastic syndromes (MDS) have previously been investigated, their prognostic significance remains controversial. We performed a meta-analysis to investigate the impact of U2AF1 mutations on MDS progression.

METHODS

Two reviewers independently extracted information such as hazard ratios (HRs) and 95% confidential intervals (CIs) for overall survival (OS) and leukemia-free survival (LFS) as well as the number of surviving patients each year after diagnosis from the included studies.

RESULTS

Thirteen studies with a total of 3038 patients were included. The summary odds ratio (OR) for U2AF1 mutations with an OS of 5 years was 0.37, the summary HR for U2AF1 mutations in OS was 1.60, and the summary OR for an OS of 5 years in patients with U2AF1^S34 and U2AF1^Q157 was 3.68. There were no significant differences in leukemia-free survival or hypomethylating therapy response between patients with and without U2AF1 mutations.

CONCLUSION

U2AF1 mutations were associated with poor survival in MDS patients, and patients with U2AF1^Q157 had a worse OS than those with U2AF1^S34. Our findings suggest that MDS patients with U2AF1 mutations could benefit more from hypomethylation therapy.

Prognostic value of U2AF1 mutant in patients with de novo myelodysplastic syndromes: a meta-analysis

U2 small nuclear RNA auxiliary factor 1 (U2AF1) mutant is the most common molecular biological abnormality in patients with myelodysplastic syndromes. Some studies have reported the prognostic impact of U2AF1 mutant in patients with de novo MDS, with discrepant results, so we do a meta-analysis about the relevant literatures to further investigate their prognostic impact on patients with de novo MDS. We conducted a literature search on databases such as PubMed, Embase, and the Cochrane Library to obtain studies on the prognosis of U2AF1 mutant in patients with de novo MDS published up to August 9, 2018. The primary endpoint was overall survival (OS), and the secondary endpoint was acute myeloid leukemia (AML) transformation. We extracted the hazard ratios (HRs) of OS and AML transformation and their 95% confidence intervals (CIs). Meta-analysis was performed by selecting a fixed-effect model or a random-effects model based on the heterogeneity between studies. A total of 14 cohort studies were included in the final meta-analysis, including 3322 patients with de no MDS, in which 390 patients were associated with U2AF1 mutant. The results showed that U2AF1 mutant had an adverse prognostic impact on OS (HR = 1.84, 95% CI: 1.45-2.33, P < 0.00001) and AML transformation (HR = 2.47, 95% CI: 1.50-4.06, P = 0.0004). U2AF1 mutant was associated with shorter OS in subgroup analyses of low- or intermediate-1-IPSS, U2AF1^S34 and U2AF1^Q157/R156. Out meta-analysis indicates that U2AF1 mutants are independent, detrimental prognostic factors for OS and AML transformation in patients with de novo MDS, as well as associating with shorter OS in subgroups of low- or intermediate-1-IPSS, U2AF1^S34 and U2AF1^Q157/R156. Further prospective studies are needed in the future, and subgroup analysis of U2AF1 subgroups is needed to obtain a more reliable basis for the impact of U2AF1 mutant on the prognosis of de novo MDS.

Molecular evidence supporting the precursor nature of atypical adenomatous hyperplasia of the prostate

Atypical adenomatous hyperplasia (AAH) of the prostate is characterized by lobular proliferation of closely packed small acini. It is hypothesized that AAH is a precursor lesion for low-grade prostate cancer arising from the transition zone. Telomere dysfunction is common during malignant transformation of epithelia. In this study, we investigate telomere shortening in AAH (n = 93), high-grade prostatic intraepithelial neoplasia (HGPIN) ( n = 68), and prostatic adenocarcinoma (PCA) ( n = 70) using quantitative fluorescence in situ hybridization. Twenty percent (19 of 93) of AAH specimens, 68% (46 of 68) of HGPIN, and 83% (58 of 70) of PCA showed significant telomere shortening. Thirty-two percent of AAH lesions had α-methylacyl-CoA racemase (AMACR) expression, a sensitive and specific marker for HGPIN and PCA. AMACR expression in AAH was seen more frequently in AAH foci with telomere shortening or coexisting PCA. Our findings indicate that a subset of AAH lesions have telomere shortening and AMACR expression, suggesting that these foci may be precursors for PCA.

Association between internet gaming addiction and leukocyte telomere length in Korean male adolescents

Internet gaming addiction (IGA) has been associated with many negative health outcomes, especially for youth. In particular, the potential association between IGA and leukocyte telomere length (LTL) has yet to be examined. In this study we compared LTL in Korean male adolescents with and without IGA and examined the association between LTL and autonomic functions. Specifically, plasma catecholamine, serum cortisol, and psychological stress levels were measured as autonomic functions. Data were collected using participant blood samples analyzed for LTL, catecholamine, and cortisol levels and a set of questionnaires to assess IGA and psychological stress levels of the participants. The LTL measurements were made using a qPCR-based technique, and the relative LTL was calculated as the telomere/single copy (T/S) ratio. T/S ratio was significantly shorter in the IGA group than in the non-IGA group (150.43 ± 6.20 and 187.23 ± 6.42, respectively; p < .001) after adjusting for age. In a univariate regression analysis, age, daily Internet gaming time, IGA score, and catecholamine level (epinephrine and norepinephrine) were significantly associated with T/S ratio. However, duration of Internet gaming exposure, dopamine, cortisol, and psychological stress levels were not found to be associated with T/S ratio. In the final multiple linear regression model, age, daily Internet gaming time, and epinephrine level showed statistically significant relationships with T/S ratio. Our results indicate that in addition to age, involvement in excessive Internet gaming may induce LTL shortening in male adolescents, which may be partially attributable to changes in autonomic function such as catecholamine level. These findings further understanding of the health effects of IGA and highlight the need for screening and intervention strategies for male adolescents with IGA.

SRSF2 mutations in myelodysplasia/myeloproliferative neoplasms

Recurrent gene mutations have been described with varying frequencies in myelodysplasia (MDS) /myeloproliferative neoplasm (MPN) overlap syndromes (MMOS). Recent work has placed significant focus on understanding the role of gene lesions involving the spliceosomal machinery in leukemogeneis. SRSF2 is a gene encoding critical spliceosomal proteins. SRSF2 mutations appear to play an important role in pathogenesis of MMOS, particularly in chronic myelomonocytic leukemia. Inhibition of splicing may be a new therapeutic approach. E7107, a spliceosome inhibitor, has been shown to differentially inhibit splicing more in SRSF2-mutant cells leading to decreased leukemia burden in mice. H3B-8800 is a small molecule modulator of spliceosome complex and has been shown to lower leukemia burden in SRSF2-P95H mutant mice. This review focuses on the incidence of mutant SRSF2 across various MMOS as well as recent clinical development of spliceosome inhibitors.

SETBP1 mutations as a biomarker for myelodysplasia /myeloproliferative neoplasm overlap syndrome

Myelodysplasia (MDS) /myeloproliferative neoplasm (MPN) overlap syndrome has been described since the 2001 WHO classification as disorders that have both proliferative and dysplastic changes simultaneously. Specific disorders include chronic myelomonocytic leukemia (CMML), juvenile myelomonocytic leukemia (JMML), BCR-ABL negative atypical chronic myeloid leukemia (aCML) and unclassifiable MDS/MPN (MPN/MDS-U). Recurrent gene mutations in these conditions have been described. Among them, SETBP1 mutations have been identified in up to 32% of aCML, 24% of JMML, 18% of CMML and 10% of MDS/MPN-U patients. The mutation hotspot lies in the amino acid residues 858–871 in the SETBP1 protein. SETBP1 mutations in MDS/MPN overlap syndrome is associated with accelerated transformation to leukemia and poor prognosis. In this review, we summarized the latest data on the role of SETBP1 mutations in the overlap syndrome. SETBP1 mutations may serve as a biomarker for the diagnosis and poor prognosis of the overlap syndrome.

Monosomy 7/del (7q) in inherited bone marrow failure syndromes: A systematic review

Inherited bone marrow failure syndromes (IBMFS) are rare cancer predisposition syndromes with an especially high risk of transformation to myelodysplastic syndrome (MDS) and/or acute myeloid leukemia (AML). We performed a retrospective systematic review of reported MDS/AML arising in the eight most common IBMFS to determine the frequency and outcome of chromosome 7 abnormalities. We identified 738 MDS/AML cases of 4,293 individuals. Monosomy 7 or del (7q) occurred in ∼17%. Greater understanding of the roles played by sequential acquisition of genetic and cytogenetic changes will provide insights into myeloid leukemogenesis and improve the surveillance and hopefully outcomes for individuals with IBMFS.

Telomeres and Telomerase in Hematopoietic Dysfunction: Prognostic Implications and Pharmacological Interventions

Leukocyte telomere length (TL) has been suggested as a marker of biological age in healthy individuals, but can also reflect inherited and acquired hematopoietic dysfunctions or indicate an increased turnover of the hematopoietic stem and progenitor cell compartment. In addition, TL is able to predict the response rate of tyrosine kinase inhibitor therapy in chronic myeloid leukemia (CML), indicates clinical outcomes in chronic lymphocytic leukemia (CLL), and can be used as screening tool for genetic sequencing of selected genes in patients with inherited bone marrow failure syndromes (BMFS). In tumor cells and clonal hematopoietic disorders, telomeres are continuously stabilized by reactivation of telomerase, which can selectively be targeted by telomerase-specific therapy. The use of the telomerase inhibitor Imetelstat in patients with essential thrombocythmia or myelofibrosis as well as the use of dendritic cell-based telomerase vaccination in AML patients with complete remissions are promising examples for anti-telomerase targeted strategies in hematologic malignancies. In contrast, the elevation in telomerase levels through treatment with androgens has become an exciting clinical intervention for patients with BMFS. Here, we review recent developments, which highlight the impact of telomeres and telomerase targeted therapies in hematologic dysfunctions.

Abnormal mRNA Expression Levels of Telomere-Binding Proteins Represent Biomarkers in Myelodysplastic Syndromes: A Case-Control Study

Objective:

As evidence was shown that abnormal shortening of telomeres begins to accumulate in myelodysplastic syndrome (MDS) patients, this study was conducted to determine the relationship between the mRNA expression levels of telomere-binding proteins (TRF1/TRF2/TIN2/TPP1/POT1/RAP1) and the risk level in MDS.

Materials and Methods:

There were 40 patients with MDS and 40 normal controls in this study. Methods including telomere content assays and quantitative reverse transcription-polymerase chain reaction were used to examine the mRNA levels of TRF1/TRF2/TIN2/TPP1/POT1/RAP1 in patients with MDS.

Results:

Compared to the normal group used as a control, the mRNA expression levels of RAP1/POT1/TPP1 of the patients with MDS were decreased, whereas their levels of TRF1/TRF2 and TIN2 were increased. A positive correlation was found between the TRF1, TRF2, and TIN2 mRNA expression levels and the risk level of the International Prognostic Scoring System (IPSS) and the World Health Organization Prognostic Scoring System (WPSS) criteria; however, a negative correlation was found between RAP1/POT1/TPP1 mRNA expression levels and the risk levels of IPSS and WPSS criteria.

Conclusion:

Because the reduction of TRF1/TRF2/TIN2 mRNA expression and the increase of RAP1/POT1/TPP1 mRNA expression are closely related to the risk levels of the IPSS and WPSS criteria in MDS, it is thought that these telomere-binding proteins could lead to abnormal telomere length and function, which cause chromosomal abnormalities in MDS. With this evidence, we suggest that those proteins’ mRNA expressions could be used as biomarkers for the assessment of the risk degree of MDS patients.

Characterization of an acquired jumping translocation involving 3q13.31-qter in a patient with de novo acute monocytic leukemia

We studied an adult with de novo acute monocytic leukemia and a dismal outcome where her leukemic cells harbored an acquired rare jumping translocation (JT). We used oligo-based array CGH (oaCGH) analysis, fluorescence in situ hybridization (FISH), and 24-color karyotyping to enhance the characterization of the JT. G-banding detected a JT involving the 3q13.3-qter chromosomal segment and the recipient chromosomal regions 17p, 8q, and 15q. Each clone with JT was associated with trisomy 8. oaCGH analysis revealed an additional submicroscopic deletion in 3q13.31 as well as small subtelomeric duplications on several chromosomes. Locus-specific FISH with BAC-based probes from the 3q13.31-q13.32 region showed great heterogeneity. Telomere FISH revealed significantly reduced telomeric content in the aberrant cells with JT compared with cytogenetically normal cells at diagnosis and in normal cells at complete remission. A literature search revealed two previous de novo AML-M5 cases of JT involving the 3q13.3-qter chromosomal segment and concomitant trisomy 8. In addition, a case with an unbalanced der(Y)t(Y;3)(q12;q13.31) and additional trisomy 8 was previously reported in a patient with de novo AML-M5. All of these cases had a dismal outcome. In the present case, and in the der(Y)t(Y;3) case, a concurrent submicroscopic deletion at 3q13.31 was observed affecting the TUSC7 gene. Duplication of 3q13.31-qter might be a non-random chromosomal abnormality with concomitant submicroscopic deletion at 3q13.31 occurring in rare cases of acute monocytic leukemia, being associated with adverse prognosis. The impact of shortened telomeres in forming the JT is reviewed.

The relationship between idiopathic cytopenias/dysplasias of uncertain significance (ICUS/IDUS) and autoimmunity

INTRODUCTION

This review examines the several lines of evidence that support the relationship between myelodysplasia and autoimmunity, i.e. their epidemiologic association, the existence of common immune-mediated physiopathologic mechanisms, and the response to similar immunosuppressive therapies. The same relationship is reviewed here considering idiopathic cytopenia of uncertain significance (ICUS) and idiopathic dysplasia of uncertain significance (IDUS), two recently recognized provisional conditions characterized by isolated/unexplained cytopenia and/or dysplasia in <10% bone marrow cells. Areas covered: The review focuses on alterations of cytokine profiles, telomere/telomerase and toll-like receptors, and on increased myelosuppressive mediators and apoptotic markers in both myelodysplasia and autoimmunity. In addition, the presence of an autoimmune reaction directed against marrow precursors is described in refractory/relapsing autoimmune cytopenias (autoimmune hemolytic anemia, immune thrombocytopenia, chronic idiopathic neutropenia), possibly contributing to their evolution to ICUS/IDUS/bone marrow failure syndromes. Expert commentary: The increasing availability of omics methods has fuelled the discussion on the role of somatic mutations in the pathogenesis of IDUS/ICUS, clonal hematopoiesis of indeterminate potential, and clonal cytopenias of undetermined significance, and in their possible evolution. Even more attracting is the involvement of the genetic background/accumulating somatic mutations in cytopenias with autoimmune alterations.