The 5q-anomaly

Haploinsufficiency of miR-143 and miR-145 reveal targetable dependencies in resistant del(5q) myelodysplastic neoplasm

Myelodysplastic neoplasms (MDS) are stem cell disorders characterized by ineffective hematopoiesis and risk of transformation to acute myeloid leukemia (AML). Chromosomal alterations are frequent in MDS, with interstitial deletion of chromosome 5q (del(5q)) being the most common. Lenalidomide is the current first-line treatment for del(5q) MDS and its efficacy relies on degradation of CK1α which is encoded by the CSNK1A1 gene located in the commonly deleted region (CDR) of chromosome 5q. However, lenalidomide-resistance is common, often secondary to loss-of-function mutations in TP53 or RUNX1. The CDR in del(5q) harbors several genes, including noncoding miRNAs, the loss of which contribute to disease phenotypes. miR-143 and miR-145 are located within the del(5q) CDR, but precise understanding of their role in human hematopoiesis and in the pathogenesis of del(5q) MDS is lacking. Here we provide evidence that deficiency of miR-143 and miR-145 plays a role in clonal expansion of del(5q) MDS. We show that insulin-like growth factor 1 receptor (IGF-1R) is a direct target of both miR-143 and miR-145. Our data demonstrate that IGF-1R inhibition reduces proliferation and viability of del(5q) cells in vitro and in vivo, and that lenalidomide-resistant del(5q) MDS cells depleted of either TP53 or RUNX1 are sensitive to IGF-1R inhibition. Resistant del(5q) MDS-L cells, as well as primary MDS marrow cells, are also sensitive to targeting of IGF-1R-related dependencies in del(5q) MDS, which include the Abl and MAPK signaling pathways. This work thus provides potential new therapeutic avenues for lenalidomide-resistant del(5q) MDS.

Low dose lenalidomide versus placebo in non-transfusion dependent patients with low risk, del(5q) myelodysplastic syndromes (SintraREV): a randomised, double-blind, phase 3 trial

BACKGROUND

Lenalidomide is the standard of care for patients who are transfusion dependent with chromosome 5q deletion (del[5q]) myelodysplastic syndromes. In the SintraREV trial, we aimed to investigate whether an early intervention of low lenalidomide doses for 2 years could delay transfusion dependency in patients with anaemia who were not transfusion dependent.

METHODS

This randomised, double-blind, phase 3 trial, was conducted at 22 sites (University Hospitals) in Spain, France, and Germany. Eligible patients were aged 18 years or older diagnosed with low-risk or intermediate-1-risk del(5q) myelodysplastic syndromes with non-transfusion-dependent anaemia (according to the IPSS), were erythropoietin-stimulating agents naive, and had an ECOG performance status of 2 or less. Patients were randomly assigned (2:1) by means of a telephone system to receive lenalidomide 5 mg daily in 28-day cycles versus placebo for 2 years. The primary endpoint was time to transfusion dependency based on blinded independent central review. Analysis were by intent-to-treat (ITT) and evaluable population. Safety analyses included all participants who received at least one dose of treatment. This trial is registered with ClinicalTrials.gov (NCT01243476) and EudraCT (2009-013619-36) and is complete.

FINDINGS

Between Feb 15, 2010, and Feb 21, 2018, 61 patients were randomly assigned to receive lenalidomide (n=40; two did not receive treatment) or placebo (n=21). The median age was 72·2 (IQR 65·4-81·9) years, 50 (82%) patients were female, and 11 (18%) were male. The median follow-up time was 60·6 (IQR 32·1-73·9) months. Regarding primary endpoint, median time to transfusion dependency was not reached (95% CI not applicable) in the lenalidomide group versus 11·6 months (95% CI 0·00-30·11) in the placebo group (p=0·0027). Lenalidomide significantly reduced the risk of transfusion dependency by 69·8% (hazard ratio 0·302, 95% CI 0·132-0·692; p=0·0046). The most frequent treatment-related adverse event was neutropenia, occurring in 24 (63%) of 38 patients in the lenalidomide group (grade 3 and 4 in 17 [45%] patients and one [3%], respectively) and in four (19%) of 21 patients in the placebo group (grade 3 in one [5%] patient). Thrombocytopenia was detected in seven (18%) of 38 patients receiving lenalidomide (grade 3 in two [5%] patients). Regarding the non-haematological toxicity, skin disorders (rash nine [23%] of 38 patients) were the most frequently described toxicities among patients receiving lenalidomide, being grade 3 in one (3%) of 38 patients. 19 serious adverse events were reported in 13 patients, 18 in the lenalidomide group and one in the placebo group, five of which were potentially related to the study drug. No treatment-related deaths were identified.

INTERPRETATION

An early approach with low doses of lenalidomide across two years delays the time to transfusion dependency and improves the rate and quality of the responses, with a manageable safety profile in patients who are non-transfusion dependent with del(5q) low-risk myelodysplastic syndromes.

FUNDING

Bristol Myers Squibb.

Rare Hematologic Malignancies and Pre-Leukemic Entities in Children and Adolescents Young Adults

There are a variety of rare hematologic malignancies and germline predispositions syndromes that occur in children and adolescent young adults (AYAs). These entities are important to recognize, as an accurate diagnosis is essential for risk assessment, prognostication, and treatment. This descriptive review summarizes rare hematologic malignancies, myelodysplastic neoplasms, and germline predispositions syndromes that occur in children and AYAs. We discuss the unique biology, characteristic genomic aberrations, rare presentations, diagnostic challenges, novel treatments, and outcomes associated with these rare entities.

Quantitative evaluation of treatment response to lenalidomide by applying fluorescence in situ hybridization for peripheral blood granulocytes in a patient with 5q- syndrome

The introduction of lenalidomide has significantly improved clinical outcomes in myelodysplastic syndrome (MDS) with isolated interstitial deletion of the long arm of chromosome 5 (del(5q)) (5q– syndrome). These days, MDS with isolated del(5q) includes cases with one additional chromosome abnormality other than monosomy 7 or del(7q), and so we need a better way to monitor tumor cells in each patient than the clinical parameters used to date. An 82-year-old woman with MDS with isolated del(5q) was treated with lenalidomide daily for 21 days in a 4-week cycle. Fluorescence in situ hybridization with CSF1R located at 5q was applied to the peripheral blood samples. Because mature lymphocytes are not involved in the MDS clone, based on the nuclear morphology, polymorphonuclear cells (PMNs) and round-shaped nuclear cells (RSNs) were separately evaluated during treatment. After a single course of treatment, the number of PMNs with del(5q) decreased; by the end of the second course of treatment, both PMNs and RSNs with del(5q) had disappeared. The dynamics of 5q– PMNs is a simple but rapid and reliable indicator to confirm the effect of lenalidomide in MDS with del(5q).

From APC to the genetics of hereditary and familial colon cancer syndromes

Hereditary colorectal cancer (CRC) syndromes attributable to high penetrance mutations represent 9-26% of young-onset CRC cases. The clinical significance of many of these mutations is understood well enough to be used in diagnostics and as an aid in patient care. However, despite the advances made in the field, a significant proportion of familial and early-onset cases remains molecularly uncharacterized and extensive work is still needed to fully understand the genetic nature of CRC susceptibility. With the emergence of next-generation sequencing and associated methods, several predisposition loci have been unraveled, but validation is incomplete. Individuals with cancer-predisposing mutations are currently enrolled in life-long surveillance, but with the development of new treatments, such as cancer vaccinations, this might change in the not so distant future for at least some individuals. For individuals without a known cause for their disease susceptibility, prevention and therapy options are less precise. Herein, we review the progress achieved in the last three decades with a focus on how CRC predisposition genes were discovered. Furthermore, we discuss the clinical implications of these discoveries and anticipate what to expect in the next decade.

Content validity of patient-reported outcomes for use in lower-risk myelodysplastic syndromes

BACKGROUND

The lower-risk (low and intermediate-1 risk based on IPSS) myelodysplastic syndrome (MDS) has a negative impact on patients' health-related quality of life (HRQoL). Patient Reported Outcomes (PROs) instruments, which are used to collect patients' HRQoL data, should have established content validity in the target population to ensure that the instrument is comprehensive and comprehensible. The present study was conducted to evaluate the content validity of the Quality of Life in Myelodysplasia Scale (QUALMS) and the Functional Assessment of Cancer Therapy-Anemia (FACT-An) PRO instruments in patients with lower-risk MDS.

METHODS

In this cross-sectional, qualitative study, 16 patients aged ≥18 years with lower-risk MDS, who were RBC transfusion dependent, literate and fluent in US-English were interviewed. Interviews were semi-structured comprising of two parts: concept elicitation (CE) explored symptoms and impacts important to patients, and cognitive debriefing (CD) assessed understanding and relevance of the QUALMS and FACT-An. A conceptual model was developed, which was used to map the concepts that emerged during CE onto the QUALMS and FACT-An to assess concept coverage and suitability of the instruments.

RESULTS

The median age of participants was 67.5 years (range: 51-91), with half being female (n = 8). Nine (56.2%) participants had intermediate-1-risk MDS and 10 (62.5%) were relapsed or refractory to erythropoiesis-stimulating agent treatment. Fatigue/tiredness (100.0%), shortness of breath (87.5%), weakness (81.2%), and low energy (75.0%) were reported most commonly and were the most bothersome symptoms as well. Of seven high-level HRQoL domains identified, activities of daily living (n = 16, 100.0%), physical functioning (n = 15, 93.8%), emotional wellbeing (n = 13, 81.3%), social functioning (n = 12, 75.0%), sleep disturbance (n = 9, 56.3%), and impact on work (n = 9, 56.3%) were the most commonly reported. For CD, the QUALMS and FACT-An were found to be mostly relevant and very well understood; response options were easy to use, and recall period was appropriate.

CONCLUSION

Both QUALMS and FACT-An demonstrated a strong face and content validity in patients with lower-risk MDS, suggesting that these instruments are appropriate for assessing HRQoL in this population.

Loss of 5q in myeloid malignancies - A gain in understanding of biological and clinical consequences

Hemizygous interstitial or terminal deletion of the long arm of chromosome 5 [del(5q)] is a recurrent cytogenetic abnormality in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). These deletions cause loss of a large contiguous chromosomal region encompassing more than 30 genes, which results in disease through haploinsufficiency of one or more genes including RPS14. In MDS, del(5q) in isolation is a lower-risk cytogenetic anomaly and is sometimes associated with a unique clinicopathological phenotype, but in AML it represents a higher-risk lesion, often denoting secondary AML arising from prior MDS. Lenalidomide effectively targets the del(5q)-bearing clone in MDS, resulting in sustained erythroid transfusion independence in most patients and cytogenetic remission in a subset of treated patients. Since the initial regulatory approval of lenalidomide for del(5q) MDS in 2005, translational research endeavors in del(5q)-associated myeloid malignancies have improved our understanding of how allelic haploinsufficiency underlies both the hematological phenotype and selective sensitivity to lenalidomide therapy. This review will focus on the molecular pathogenesis of del(5q) in myeloid malignancies, clinical development of lenalidomide and emerging data on lenalidomide-refractory del (5q) MDS, and possible novel targeted therapeutic strategies.

The Evolution of the Ribosomal Protein-MDM2-p53 Pathway

The progression of our understanding of ribosomal proteins as static building blocks of the ribosome to highly integrated sensors of p53 surveillance and function has achieved a tremendous rate of growth over the past several decades. As the workhorse of the cell, ribosomes are responsible for translating the genetic code into the functional units that drive cell growth and proliferation. The seminal identification of ribosomal protein binding to MDM2, the negative regulator of p53, has evolved into a paradigm for ribosomal protein-MDM2-p53 signaling that extends into processes as diverse as energy metabolism to proliferation. The central core of signaling occurs when perturbations to rRNA synthesis, processing, and assembly modulate the rate of ribosome biogenesis, signaling a nucleolar stress response to p53. This has led to identification of a number of disease pathologies related to ribosomal protein dysfunction that are manifested as developmental disorders or cancer. Advancing research into the basic mechanics of ribosomal protein-MDM2-p53 signaling is paving the way for novel translational research into biomarker identification and therapeutic strategies for ribosome-related diseases.

Nucleophosmin mutation in de-novo acute myeloid leukemia

OBJECTIVE

Acute myeloid leukemia (AML) with mutated nucleophosmin gene (NPM1) has distinctive clinical, hematological and molecular features, and is included as a provisional entity in 2008 World Health Organization classification. In this study, we analyzed the frequency and features of AML with mutated NPM1 in Indian patients.

METHODS

One-hundred consecutive patients of de-novo AML were evaluated for NPM1 mutation and their features were compared with unmutated NPM1 patients.

RESULTS

AML with mutated NPM1 was seen in 21% cases. There was female preponderance with median age of 51 years. Distinguishing Features in mutated group were less bleeding manifestations and bone pains; more lymphadenopathy; higher median total leukocyte and platelet count; less frequency of pancytopenia and more preserved megakaryocytes. Morphologically, cup-shaped nuclei in peripheral blood blasts correlated with NPM1 mutation (p <0.01), but not bone marrow blasts. Among the French-American-British subtypes, NPM1 mutation was seen in M1, M4 and M2 subtypes but not in M0 and M3. Immunophenotypically, there was statistically significant negativity for CD34, strong association with monocytic markers (especially CD11c), CD123 was seen at higher frequency and higher mean fluorescence intensity (MFI) values for CD33 were observed in mutated cases.

CONCLUSIONS

Important findings in this study that have not been highlighted in detail in previous studies in NPM1-mutated cases include less bleeding manifestations and bone pains, lower frequency of pancytopenia and more preserved magakaryocytes, higher CD123 expression and higher MFI values for CD33. Presence of blasts with cup-shaped nuclei correlated with NPM1 mutation.

der(5;17)(p10;q10) is a recurrent but rare whole-arm translocation in patients with hematological neoplasms: a report of three cases

We report the cases of 3 patients with hematological malignancies and complex karyotypes involving der(5; 17) (p10;q10), which results in the loss of 5q and 17p. Although deletions of 5q and 17p are recurrent abnormalities in hematological disease, only about 20 cases harboring der(5; 17) (p10;q10) have been reported. We address the tumorigenesis and morphological characteristics of hematological malignancies involving der(5; 17)(p10;q10), along with a review of the literature.

The pur protein family: genetic and structural features in development and disease

The Pur proteins are an ancient family of sequence-specific single-stranded nucleic acid-binding proteins. They bind a G-rich element in either single- or double-stranded nucleic acids and are capable of displacing the complementary C-rich strand. Recently several reports have described Pur family member knockouts, mutations, and disease aberrations. Together with a recent crystal structure of Purα, these data reveal conserved structural features of these proteins that have been adapted to serve functions unique to higher eukaryotes. In humans Pur proteins are critical for myeloid cell development, muscle development, and brain development, including trafficking of mRNA to neuronal dendrites. Pur family members have been implicated in diseases as diverse as cancer, premature aging, and fragile-X mental retardation syndrome.

The incidence of myelodysplastic syndromes in Western Greece is increasing

Descriptive epidemiology of the myelodysplastic syndromes (MDS) is always interesting and may reveal time-dependent and geographical variations, as well as occupational exposure. Epidemiological data in Greece are not available by now. We have collected and analyzed medical records of all patients with a documented diagnosis of MDS, performed by an expert hematologist and/or hematopathologist, in the geographical area of Western Greece, during the 20-year period, defined between 1990 and 2009. We have then calculated and described demographic and clinical features of the diagnosed MDS patient population, and assessed the incidence and prevalence rates of MDS in Western Greece, during the above-mentioned period. A total of 855 patients with newly diagnosed MDS have been identified. Refractory anemia was the most common subtype in both FAB and WHO classification systems and in both genders. Del-5q and RARS were more commonly encountered among females, and the dysplastic subtype of chronic myelomonocytic leukemia among males. Trisomy 8 was the most common single cytogenetic abnormality. The crude mean annual incidence rate of MDS was 6.0 per 100,000 inhabitants aged ≥15 years old (all subtypes according to FAB), and it was 4.8 per 100,000 when CMML and RAEB-T were excluded. Crude incidence rate was higher in rural than in urban areas, but this finding was not confirmed after age standardization. Age-standardized mean annual incidence rate in men was 7.9/100,000 and in women 3.4/100,000. A continuously increasing incidence rate of MDS has been observed throughout the study period.

Incidence of 17p deletions and TP53 mutation in myelodysplastic syndrome and acute myeloid leukemia with 5q deletion

TP53 mutations are frequent in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) with complex karyotype that include del(5q) and are often associated with deletion of 17p. They have also recently been observed in MDS with isolated del(5q). We assessed the incidence of 17p deletion detected by fluorescence in situ hybridization (FISH) and of TP53 mutations detected by direct sequencing and their correlation and prognostic value in 26 MDS and 17 AML with del(5q). In the 20 cases with isolated del(5q) or one additional abnormality, no 17p deletion was found and 3 of the 18 cases analyzed (17%) had TP53 mutation. In the 23 patients with complex karyotype, 17p deletion was suspected by conventional cytogenetics in 15 cases and confirmed by FISH in 10 of them, while TP53 mutation was found in 8 of the 15 patients tested (53%), only five of whom had 17p deletion. In the whole patient series, TP53 mutations were associated with shorter survival (P = 0.07). We confirm the existence of TP53 mutations in 17% of MDS with isolated del(5q). In patients with del(5q) and complex karyotype, FISH and direct sequencing are complementary techniques to analyze TP53 abnormalities. Our findings also suggest that sequencing of the TP53 gene should be included in the study of patients with del(5q) as a single abnormality or in complex karyotype before lenalidomide treatment.

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.

Disease-associated patterns of disomic chromosomes in hyperhaploid neoplasms

The chromosome number of human tumors varies widely, from near-haploidy to more than decaploidy. Overt hyperhaploid (24-34 chromosomes) tumors constitute a small minority (0.2-0.3% of cytogenetically investigated lesions), but occur in many different disease entities. In these karyotypes, most chromosomes are present in one copy; one or a few chromosomes are disomic. Published reports on 141 strictly hyperhaploid tumors, supplemented with nine previously unpublished cases, were used for evaluating the pattern of disomic chromosomes. Only one tumor type, acute lymphoblastic leukemia (ALL), was sufficiently common (n = 75) to allow proper evaluation; other neoplasms were lumped together in as reasonably logical groups as possible, including 10 myeloid leukemias (ML), nine plasma cell neoplasms (PCN), 13 chondrosarcomas (CS), 11 soft tissue tumors (STT), nine adeno- or squamous cell carcinomas (ASC), and eight tumors of the nervous system (TNS); the remaining 15 tumors could not be grouped. It was evident that the pattern of disomies is nonrandom. Moreover, unique signatures for each tumor group were detected. Among ALL, most disomies were independent of age and gender, except for disomy 10, which was overrepresented in females. Chromosome 21 was invariably disomic, whereas chromosome 17 was always monosomic. The most frequent disomies were two gonosomes in ML, chromosomes 7, 9, 11, 3, 18, and 19 in PCN, 7, 5, 20, 19, and 21 in CS, 20 in STT, 7 in ASC, and 1, 7, and 9 in TNS. Chromosome 1 was often partially disomic, due to unbalanced structural rearrangements, with segment 1q21-31 in common. Doubling of the hyperhaploid clone was found in at least one-third of the cases, apart from in ML where only one of 10 cases showed chromosome doubling. The present findings indicate that retention of disomy for some chromosomes is pathogenetically important and that the chromosome(s) maintained in two copies is related to cell type or histological context.

Important genes in the pathogenesis of 5q- syndrome and their connection with ribosomal stress and the innate immune system pathway

Myelodysplastic syndrome (MDS) with interstitial deletion of a segment of the long arm of chromosome 5q [del(5q)] is characterized by bone marrow erythroid hyperplasia, atypical megakaryocytes, thrombocythemia, refractory anemia, and low risk of progression to acute myeloid leukemia (AML) compared with other types of MDS. The long arm of chromosome 5 contains two distinct commonly deleted regions (CDRs). The more distal CDR lies in 5q33.1 and contains 40 protein-coding genes and genes coding microRNAs (miR-143, miR-145). In 5q-syndrome one allele is deleted that accounts for haploinsufficiency of these genes. The mechanism of erythroid failure appears to involve the decreased expression of the ribosomal protein S14 (RPS14) gene and the upregulation of the p53 pathway by ribosomal stress. Friend leukemia virus integration 1 (Fli1) is one of the target genes of miR145. Increased Fli1 expression enables effective megakaryopoiesis in 5q-syndrome.

Molecular dissection of the 5q deletion in myelodysplastic syndrome

The 5q-syndrome is a subtype of myelodysplastic syndrome (MDS) with a defined clinical phenotype associated with heterozygous deletions of chromosome 5q. While no genes have been identified that undergo recurrent homozygous inactivation, functional studies have revealed individual genes that contribute to the clinical phenotype of MDS through haplo-insufficient gene expression. Heterozygous loss of the RPS14 gene on 5q leads to activation of p53 in the erythroid lineage and the macrocytic anemia characteristic of the 5q-syndrome. The megakaryocytic and platelet phenotype of the 5q-syndrome has been attributed to heterozygous deletion of miR145 and miR146a. Murine models have implicated heterozygous loss of APC, EGR1, DIAPH1, and NPM1 in the pathophysiology of del(5q) MDS. These findings indicate that the phenotype of MDS patients with deletions of chromosome 5q is due to haplo-insufficiency of multiple genes.

A randomized phase 3 study of lenalidomide versus placebo in RBC transfusion-dependent patients with Low-/Intermediate-1-risk myelodysplastic syndromes with del5q

This phase 3, randomized, double-blind study assessed the efficacy and safety of lenalidomide in 205 red blood cell (RBC) transfusion-dependent patients with International Prognostic Scoring System Low-/Intermediate-1-risk del5q31 myelodysplastic syndromes. Patients received lenalidomide 10 mg/day on days 1-21 (n = 69) or 5 mg/day on days 1-28 (n = 69) of 28-day cycles; or placebo (n = 67). Crossover to lenalidomide or higher dose was allowed after 16 weeks. More patients in the lenalidomide 10- and 5-mg groups achieved RBC-transfusion independence (TI) for ≥ 26 weeks (primary endpoint) versus placebo (56.1% and 42.6% vs 5.9%; both P < .001). Median duration of RBC-TI was not reached (median follow-up, 1.55 years), with 60% to 67% of responses ongoing in patients without progression to acute myeloid leukemia (AML). Cytogenetic response rates were 50.0% (10 mg) versus 25.0% (5 mg; P = .066). For the lenalidomide groups combined, 3-year overall survival and AML risk were 56.5% and 25.1%, respectively. RBC-TI for ≥ 8 weeks was associated with 47% and 42% reductions in the relative risks of death and AML progression or death, respectively (P = .021 and .048). The safety profile was consistent with previous reports. Lenalidomide is beneficial and has an acceptable safety profile in transfusion-dependent patients with Low-/Intermediate-1-risk del5q myelodysplastic syndrome. This trial was registered at www.clinicaltrials.gov as #NCT00179621.

Prognostic molecular markers in myelodysplastic syndromes

Cytogenetic findings in myelodysplastic syndromes play an important role in diagnosis, prognostication and clinical decision making. Therefore, they became an important aspect in scoring systems such as the International Prognostic Scoring System (IPSS) and the WHO-adapted Prognostic Scoring System (WPSS). Ongoing efforts to refine the categorization of karyotypes with regard to prognosis and therapeutic options will change scoring systems in the near future. In order to learn more about the pathophysiology of myelodysplastic syndromes, various molecular genetic aberrations are identified and their impact on prognosis discussed. New screening methods such as gene expression or single nucleotide polymorphism analysis are good candidates to find entrance in clinical practice in the future as they are useful tools in further elucidation of the underlying defects in myelodysplastic syndromes and the development of more specific classifications of the disease concerning risk assessment.

Isochromosome 5p and related anomalies: a novel recurrent chromosome abnormality in myeloid disorders

Loss of material from chromosome arm 5q is a common finding in patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). Fluorescence in situ hybridization with a panel of different types of probes, used as a complement to conventional cytogenetics, revealed that 7 of 148 patients (4.7%) with abnormalities of chromosome 5 had an i(5)(p10), an idic(5)(q11), or a structurally rearranged i(5)(p10). Three patients had MDS and four had AML. Six of the patients were female, and one was male; age at diagnosis ranged from 56 to 85 years. All patients but one had a complex karyotype. Isochromosome of the short arm of chromosome 5 and its related abnormalities such as idic(5)(q11) and structurally rearranged i(5)(p10) are rare but recurrent abnormalities; their identification requires a combination of conventional and molecular cytogenetic techniques. The biological and clinical significance cannot yet be assessed, not only because too few cases have been described but also because these abnormalities are usually part of a complex karyotype.

Closing in on the pathogenesis of the 5q- syndrome

Evaluation of: Barlow JL, Drynan LF, Hewett DR et al. A p53-dependent mechanism underlies macrocytic anemia in a mouse model of human 5q- syndrome. Nat. Med. 16(1), 59-66 (2010); and Starczynowski DT, Kuchenbauer F, Argiropoulos B et al. Identification of miR-145 and miR-146a as mediators of the 5q- syndrome phenotype. Nat. Med. 16(1), 49-58 (2009). Patients with 5q- syndrome are characterized by macrocytic anemia, normal to elevated platelet counts, and a propensity to develop acute myeloid leukemia. The 5q- syndrome is believed to be a clonal disorder of the hematopoietic precursors. Until recently, little was known regarding the molecular pathogenesis of this malignancy. Two recently published studies using genetic approaches have unraveled a small array of genes whose alteration recapitulates critical features of the 5q- syndrome including dysplasia, clonal dominance, and progression to acute myeloid leukemia.

Ectopic expression of C/EBPalpha and ID1 is sufficient to restore defective neutrophil development in low-risk myelodysplasia

BACKGROUND

In patients with myelodysplasia, a general defect in the multipotent stem-cell compartment results in disturbed proliferation and differentiation of the erythroid, megakaryocytic and myeloid lineages. Although a number of genetic defects in myelodysplastic progenitor cells have been described, the intracellular signaling pathways underlying aberrant regulation of myelopoiesis remain relatively undefined.

DESIGN AND METHODS

Here, an ex vivo differentiation system was used to selectively screen for molecules improving defective hematopoiesis in myelodysplastic CD34(+) progenitor cells.

RESULTS

Bone marrow-derived CD34(+) cells isolated from patients with low-risk myelodysplastic syndrome showed impaired capacity to proliferate and differentiate as well as increased levels of apoptosis. In an attempt to improve the expansion and differentiation of the myelodysplastic CD34(+) progenitors, cells were treated with the p38MAPK pharmacological inhibitor SB203580, or retrovirally transduced to ectopically express active protein kinase B (PKB/c-akt), or the transcriptional regulators STAT5, C/EBPalpha or ID1. Whereas treatment of progenitors with SB203580, PKB or STAT5 did not enhance neutrophil development, ID1- and C/EBPalpha-transduced cells exhibited increased granulocyte/macrophage colony formation. Furthermore, ectopic expression of C/EBPalpha resulted in improved neutrophil maturation.

CONCLUSIONS

These data suggest that targeting the ID1 and C/EBPalpha transcriptional regulators may be of benefit in the design of novel therapies for low-risk myelodysplasia.

Van-den Berghe's 5q- syndrome in 2008

Van Den Berghe established 5q- syndrome as a discrete clinical entity in 1974 when he described patients with macrocytic anaemia, thrombocytosis, dyserythropoiesis, hypolobulated megakaryocytes and an interstitial deletion within chromosome 5q. With del(5q) as the sole cytogenetic abnormality, 5q- syndrome represents an opportunity to define precisely the molecular defect(s) underlying the pathogenesis of this disease. The commonly deleted region in 5q- syndrome, which is distinct from that in patients with complex cytogenetic changes that include del(5q), includes the ribosomal protein S14 locus and it has been proposed that that loss of an RPS14 allele accounts for the 5q- syndrome phenotype. However, this hypothesis fails to explain the growth advantage of the 5q- syndrome clone and it is evident that ribosomal protein defects are not specific to 5q- syndrome, as they are found in other bone marrow failure syndromes. Lenalidomide therapy leads to normalization of both haematological and cytogenetic parameters in the majority of 5q- syndrome patients. This review examines the potential role of several genes, including RPS14, in the pathogenesis of the 5q- syndrome and recent advances in clinical management, with particular emphasis on the role and mechanism of action of lenalidomide.

Unusual findings in two patients with acquired deletions of the long arm of chromosome 5 (5q-)

Two patients with acquired deletions of the long arm of chromosome 5 (5q-) are presented and discussed. For both, clinical and other laboratory tests are highly atypical of patients with haematological malignancy characterized by 5q-. These unusual presentations of the 5q- anomaly further emphasize the heterogeneity of clinical presentations associated with this acquired chromosomal abnormality.

The IRF family transcription factors in immunity and oncogenesis

The interferon regulatory factor (IRF) family, consisting of nine members in mammals, was identified in the late 1980s in the context of research into the type I interferon system. Subsequent studies over the past two decades have revealed the versatile and critical functions performed by this transcription factor family. Indeed, many IRF members play central roles in the cellular differentiation of hematopoietic cells and in the regulation of gene expression in response to pathogen-derived danger signals. In particular, the advances made in understanding the immunobiology of Toll-like and other pattern-recognition receptors have recently generated new momentum for the study of IRFs. Moreover, the role of several IRF family members in the regulation of the cell cycle and apoptosis has important implications for understanding susceptibility to and progression of several cancers.

Treatment of myelodysplastic syndromes with 5q deletion before the lenalidomide era; the GFM experience with EPO and thalidomide

Anemia in MDS with 5q deletion was generally considered, until the advent of lenalidomide, unresponsive to available treatments. We analyzed erythroid response to erythropoetin (EPO) or darbepoetin (DAR) and thalidomide in MDS with 5q deletion treated by French centers (GFM) and in whom karyotype was successfully performed. Of 345 patients treated with EPO or DAR+/-G-CSF, 48 had 5q deletion. The response rate was 46% (31% major, 15% minor) according to International Working Group (IWG) 2000 criteria versus 64% in patients without 5q deletion (p=0.03). According to IWG 2006 criteria, the response rate in patients with 5q deletion was 39% versus 52% in patients without 5q deletion (p=0.10). Mean duration of response was 14 months versus 25 months (IWG 2000) and 13 months versus 27 months (IWG 2006) in 5q deletion and non-5q deletion patients (p=0.019 and 0.003, respectively). Of 120 MDS treated with thalidomide, all of whom had successful cytogenetic analysis, 37% of the 24 patients with 5q deletion responded (IWG 2000 criteria, 20% major, 17% minor) with a mean duration of 9.5 months, versus 32% (18% major, 14% minor) in MDS without 5q deletion and a mean response duration of 9 months (p=NS). Our results confirm that response rates to EPO or DAR and thalidomide are clearly inferior to those obtained with lenalidomide.

Fluorescence in situ hybridization analysis of 110 hematopoietic disorders with chromosome 5 abnormalities: do de novo and therapy-related myelodysplastic syndrome-acute myeloid leukemia actually differ?

A retrospective cytogenetic study of acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS) was conducted by the Groupe Francophone de Cytogénétique Hématologique (GFCH) to evaluate the structural abnormalities of chromosome 5 associated with other chromosomal abnormalities, in particular of chromosome 7, in these pathologies. In all, 110 cases of AML/MDS were recruited based on the presence of chromosome 5 abnormalities under conventional cytogenetics and supplemented by a systematic fluorescence in situ hybridization study of chromosomes 5 and 7. The abnormalities of the long arm of chromosome 5 (5q) were deletions of various sizes and sometimes cryptic. The 5q abnormalities were associated with translocations in 54% of cases and were simple deletions in 46%. In 68% of cases, 5q deletions were associated with chromosome 7 abnormalities, and 90% of these presented a complex karyotype. Of the 110 patients, 28 had a hematopoietic disorder secondary to chemotherapy, radiotherapy, or both. Among 82 patients with de novo AML/MDS, 63 were older than 60 years. Chromosomal abnormalities often associated hypodiploidy and chromosome 5 and 7 abnormalities in complex karyotypes, features resembling those of secondary hemopathies. Systematic investigation of the exposure to mutagens and oncogenes is thus essential to specify the factors potentially involved in MDS/AML with 5q abnormalities.

Redefining monosomy 5 by molecular cytogenetics in 23 patients with MDS/AML

Deletion of the long arm of chromosome 5 [del(5q)] or loss of a whole chromosome 5 (-5) is a common finding, arising de novo in 10% of patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) and in 40% of patients with therapy-related MDS or AML. We investigated by molecular cytogenetics 23 MDS/AML patients for whom conventional cytogenetics detected a monosomy 5. Monosomy 5 was redefined as unbalanced or balanced translocation and ring of chromosome 5. Loss of 5q material was identified in all 23 patients, but one. One copy of EGR1(5q31) or CSF1R(5q33-34) genes was lost in 22 of the 23 patients. Chromosome 5p material was a constant chromosomal component of derivative chromosomes or rings in all patients, but one. Sequential fluorescent in situ hybridization studies with whole chromosome paints and region-specific probes, used as a complement to conventional cytogenetic analysis, allow a better interpretation of karyotypes in MDS/AML patients.

Acute myeloid leukemia carrying cytoplasmic/mutated nucleophosmin (NPMc+ AML): biologic and clinical features

The nucleophosmin (NPM1) gene encodes for a multifunctional nucleocytoplasmic shuttling protein that is localized mainly in the nucleolus. NPM1 mutations occur in 50% to 60% of adult acute myeloid leukemia with normal karyotype (AML-NK) and generate NPM mutants that localize aberrantly in the leukemic-cell cytoplasm, hence the term NPM-cytoplasmic positive (NPMc+ AML). Cytoplasmic NPM accumulation is caused by the concerted action of 2 alterations at mutant C-terminus, that is, changes of tryptophan(s) 288 and 290 (or only 290) and creation of an additional nuclear export signal (NES) motif. NPMc+ AML shows increased frequency in adults and females, wide morphologic spectrum, multilineage involvement, high frequency of FLT3-ITD, CD34 negativity, and a distinct gene-expression profile. Analysis of mutated NPM has important clinical and pathologic applications. Immunohistochemical detection of cytoplasmic NPM predicts NPM1 mutations and helps rationalize cytogenetic/molecular studies in AML. NPM1 mutations in absence of FLT3-ITD identify a prognostically favorable subgroup in the heterogeneous AML-NK category. Due to their frequency and stability, NPM1 mutations may become a new tool for monitoring minimal residual disease in AML-NK. Future studies should focus on clarifying how NPM mutants promote leukemia, integrating NPMc+ AML in the upcoming World Health Organization leukemia classification, and eventually developing specific antileukemic drugs.

5q- syndrome in a child with slowly progressive pancytopenia: a case report and review of the literature

5q- syndrome is a rare myelodysplastic process occurring predominately in middle aged to elderly women. In children, myelodysplasia of all types is rare and 5q- syndrome is exceptionally rare. Only 6 cases of 5q- associated myelodysplasia have been reported in children and all 6 cases had blast counts >5% and/or additional cytogenetic abnormalities. We report a case of 5q- syndrome in a girl who presented with macrocytosis and intermittent pancytopenia at age 5. Cytogenetic studies at age 8 revealed a large interstitial deletion of chromosome 5q without other cytogenetic abnormalities. The patient was clinically stable until age 11, when she became transfusion dependent and severely neutropenic. Subsequently, she underwent a successful unrelated cord blood transplant. To our knowledge, this is the first reported pediatric case meeting the strict criteria for 5q- syndrome.

Biological and prognostic significance of chromosome 5q deletions in myeloid malignancies

The presence of del(5q), either as the sole karyotypic abnormality or as part of a more complex karyotype, has distinct clinical implications for myelodysplastic syndromes (MDS) and acute myeloid leukemia. The 5q- syndrome, a subtype of low-risk MDS, is characterized by an isolated 5q deletion and <5% blasts in the bone marrow and can serve as a useful model for studying the role of 5q deletions in the pathogenesis and prognosis of myeloid malignancies. Recent clinical results with lenalidomide, an oral immunomodulatory drug, have shown durable erythroid responses, including transfusion independence and complete cytogenetic remissions in patients with del(5q) MDS with or without additional chromosomal abnormalities. These results indicate that lenalidomide can overcome the pathogenic effect of 5q deletion in MDS and restore bone marrow balance. The data provide important new insights into the pathobiology of 5q chromosomal deletions in myeloid malignancies.

Treatment of the 5q– Syndrome

Defined by isolated del 5q and no excess of marrow blasts, the “5q– syndrome” is a specific type of myelodysplastic syndrome (MDS) with particular characteristics, including severe anemia, frequent thrombocytosis, typical dysmegakaryopoiesis and favorable outcome. Its pathogenesis remains uncertain, in particular the role of inactivation of gene(s) situated in 5q. It should be differentiated from other MDS with del 5q having an excess of marrow blasts and/or additional cytogenetic abnormalities, which carry a poor prognosis.

Until the advent of lenalidomide, repeated RBC transfusions were generally the only treatment of the 5q– syndrome, which was resistant to other therapeutic approaches. Lenalidomide can lead to RBC transfusion independence in at least two thirds of cases of the 5q– syndrome, two thirds of those responses persisting after 2 years of treatment. Importantly, not only reversal of anemia but also frequent complete pathological and cytogenetic responses are obtained. Grade 3 or 4 neutropenia and thrombocytopenia, especially during the first 6 to 8 weeks of treatment, are the major side effect of lenalidomide, justifying close monitoring of blood counts and regular patient visits.

Preliminary results suggest that lenalidomide is also very active in MDS with del 5q other than the 5q–syndrome. Although its mechanism of action remains uncertain, lenalidomide appears to target specifically the del 5q clone. By doing this, lenalidomide may have an effect on disease course and survival, which is currently being assessed in clinical trials.

Nucleophosmin gene mutations are predictors of favorable prognosis in acute myelogenous leukemia with a normal karyotype

Nucleophosmin (NPM1) exon-12 gene mutations are the hallmark of a large acute myelogenous leukemia (AML) subgroup with normal karyotype, but their prognostic value in this AML subset has not yet been determined. We screened 401 AML patients with normal karyotype treated within the German AML Cooperative Group Protocol 99 (AMLCG99) study for NPM1 mutations. Results were related with partial tandem duplications within the MLL gene (MLL-PTD), Fms-like tyrosine kinase 3–length mutations (FLT3-LM), the tyrosine kinase domain of FLT3 (FLT3-TKD), NRAS, KIT, and CEBPA mutations and with clinical characteristics and outcome. NPM1 mutations were detected in 212 (52.9%) of 401 patients. Fourteen mutations, including 8 new variants, were identified. NPM1-mutated cases associated frequently with FLT3 mutations but rarely with other mutations. The NPM1-mutated group had a higher complete remission (CR) rate (70.5% vs 54.7%, P = .003), a trend to a longer overall survival (OS; median 1012 vs 549 days, P = .076), and significantly longer event-free survival (EFS; median 428 vs 336 days; P = .012). The favorable impact of NPM1 mutations on OS and EFS clearly emerged in the large group (264 [66.8%] of 395 cases) of normal-karyotype AML without FLT3-LM. This positive effect was lost in the presence of a concomitant FLT3-LM, since survival of the NPM1+/FLT3-LM+ double positive was similar to NPM1–/FLT3-LM+ cases. In conclusion, this study demonstrates that NPM1+/FLT3-LM– mutations are an independent predictor for a favorable outcome in AML with normal karyotype.

The 5q- syndrome

The 5q- syndrome is a distinct hematological disorder with typical laboratory, morphological, cytogenetic, molecular, and prognostic features. It is defined as a myelodysplastic syndrome with a medullary blast count <5% and an isolated interstitial deletion of the long arm of chromosome 5, including bands q31-q33. The molecular basis of this disease has not yet been fully elucidated, but there is evidence that a commonly deleted region of 1.5 Mb harbors one or several tumor suppressor genes, the loss of which being the basic event leading to disease activity. The 5q- deletion has been demonstrated in very early hematopoietic precursors, including CD34+CD133+ and CD34+CD38-Thyl+ cells. Analysing data of 60 patients with the 5q- syndrome that were followed over a period of up to 28 years, we found a median age at diagnosis of 66.8 years and a female preponderance with a male to female ratio of 1:1.5. Anemia is usually macrocytic and combined with low reticulocyte counts and high erythropoetin levels. Three types of cytogenetic deletion are most prevalent: del(5)(q13q33), del(5)(q13q31) and del(5)(q22q33). The 5q- syndrome has a good prognosis with a median overall survival of 107 months at a median follow-up of 53 months, and a low probability of transformation to AML. An increase of the medullary blast count to > or =5% or the addition of one karyotypic anomaly severely reduces median overall survival. The most promising therapeutic approach is the novel thalidomide analogue CC5013 that is currently evaluated in an international phase II study.