Correlations between cytogenetics and morphology in myelodysplastic syndromes

Diagnostics and Prognostication of Myelodysplastic Syndromes

MDS are a heterogeneous and complex group of clonal hematological neoplasms arising from a hematopoietic stem cell, and characterized by ineffective hematopoiesis, resulting in increased apoptosis in the bone marrow and peripheral cytopenia, which involves one or more lineages. Epigenetic changes are reported as ‘founder’ mutations in the case of MDS. Its incidence in the general population has been reported as five new MDS diagnoses per 100,000 people. It affects men more frequently than it does women, and its incidence increases with age. The diagnostic classification, now in use, is the one of the World Health Organization, revised in August 2016. It recognizes six distinct entities in addition to a provisional entity of childhood. In most of the cases, diagnosis is based on the morphologic quantitative and qualitative evaluation of the peripheral blood and bone marrow using basic hematological techniques. Bone marrow biopsy and flow cytometric immunophenotyping also offer support for further diagnostic elucidation, while cytogenetics and molecular genetics are presently fully integrated into prognostication, treatment processes, and decision-making.

Myelodysplastic syndromes with deletions of chromosome 11q lack cryptic MLL rearrangement and exhibit characteristic clinicopathologic features

Deletions of chromosome 11q[del(11q)] as part of a non-complex karyotype are infrequent in myelodysplastic syndromes (MDS), leaving the clinicopathologic and genetic features largely undefined. From three large medical centers over a 10-year period, we identified 32 MDS cases where del(11q) was present either as a sole (n=23) or associated with another abnormality (n=9), showing an overall 0.6% frequency in MDS. These patients included 15 men and 17 women, with a median age of 68 years. Three were therapy-related, and 29 were primary MDS. These cases were characterized by transfusion-dependent anemia (65%); frequent ring sideroblasts (RS) (59%); bone marrow hypocellularity (22%), and less severe thrombocytopenia. With a median follow-up of 32 months, 9/24 (38%) cases progressed to acute myeloid leukemia (AML), and the overall survival (OS) was 35 months (3-105). Fluorescence in situ hybridization (FISH) showed MLL deletion in 6/10 cases, but no cryptic MLL translocations in all 15 MDS cases tested. In contrast, FISH performed in AML with del(11q) showed MLL rearrangement in 3/17 (18%) cases. In summary, del(11)q occurring in a non-complex karyotype is predominantly associated with primary MDS, lack of cryptic MLL rearrangements, and shows characteristic clinicopathological features. These clinicopathological features are likely attributed to commonly deleted regions of 11q and their involved genes.

The significance of bone marrow cell morphology and its correlation with cytogenetic features in the diagnosis of MDS-RA patients

Besides cytopenia, dysplasia is crucial characteristic of MDS-RA. To summarize the morphological features that contribute to the diagnosis of MDS-RA, 48 RA patients with abnormal karyotype were analyzed for the features of morphological and cytogenetical abnormalities and the relationships between them. 46 MDS-RA patients with normal karyotype and 207 patients with non-MDS anemia were enrolled into control groups. More conspicuous and diverse dysplasia can be found in abnormal karyotype MDS-RA than those in control groups (P<0.05). Apparent dysplasia in granulocyte and megakaryocytoid lineages may provide valuable evidence for the diagnosis. Dysplasia occurred more frequently in patients with severe chromosome abnormalities.

Antithymocyte globulin (ATG)-based therapy in patients with myelodysplastic syndromes

The purpose of this study was to determine the efficacy of and tolerance to antithymocyte globulin (ATG)-based therapy in patients with myelodysplastic syndrome (MDS). Therapy consisted of ATG 40 mg/kg/day daily intravenously (i.v.) for 4 days; cyclosporine daily orally for 6 months with levels titrated between 200 and 400 mg/dl; and methylprednisone 1 mg/kg i.v. daily before each dose of ATG. Of 32 patients treated, 31 patients were evaluable. The median age was 59 years (range, 28-79 years). A total of 18 patients had refractory anemia (RA) or RA with ringed sideroblasts (RARS), 10 patients had RA with excess blasts (RAEB), two patients had RAEB in transformation, and one patient had chronic myelomonocytic leukemia. ATG, cyclosporine, and methylprednisone induced complete (N=4) or partial (N=1) remission in five patients (16% of total; RA, two patients; RARS, two patients; and RAEB, one patient). Durable complete remissions were observed in three of 18 patients (17%) with RA (N=1) or RARS (N=2) (12, 41+, and 60+ months). The most common adverse events were fever and allergic reactions. Hepatic and renal dysfunction, albeit consistently reversible, occurred in 19 and 13% of the patients, respectively. In conclusion, an ATG-based regimen can produce durable complete remissions in a subset of patients with MDS.

Distinct clinical outcomes for cytogenetic abnormalities evolving from aplastic anemia

A serious complication of aplastic anemia (AA) is its evolution to clonal hematologic diseases such as myelodysplasia (MDS) and leukemia, which is usually associated with the appearance of a cytogenetic abnormality in bone marrow cells. We present here an analysis of a cohort of 30 patients with otherwise typical AA in whom clonal karyotypic evolution was observed during frequent periodic marrow examinations. The actuarial risk for this complication has been estimated in other studies at around 15% at 5 years. Conversion from normal to abnormal karyotype occurred at a constant rate after initial diagnosis, with about 50% of cases developing within the first 30 months. Transient chromosomal abnormalities were infrequent. Clinically, AA patients with clonal cytogenetic patterns were heterogenous; a variety of karyotypic defects with numerical and structural abnormalities of chromosome 7 accounted for 40% of all cases followed by trisomy 8, structural and numerical abnormalities of chromosome 13, deletion of Y chromosome, and complex cytogenetic abnormalities. Unlike in primary MDS, aberrancies of chromosome 5 and 20 were infrequent. The clinical course depended on the specific abnormal cytogenetic pattern. Most deaths related to leukemic transformation occurred in patients with abnormalities of chromosome 7 or complex cytogenetic alterations or both. Evolution of chromosome 7 abnormalities was seen most often in refractory patients who had failed to respond to therapy. In contrast, trisomy 8 developed in patients with good hematologic responses who often required chronic immunosuppression with cyclosporine A (CsA), and survival was excellent. Although AA patients with monosomy 7 showed a similar prognosis to those with primary MDS, trisomy 8 in AA appears to have a more favorable prognosis than in MDS.

Chromosome 11 abnormalities in myelodysplastic syndromes

Cytogenetic studies were performed in 140 patients with myelodysplastic syndrome (MDS) at diagnosis. Chromosome 11 anomalies were found in 7 cases (5%); 2 of these patients had refractory anemia (RA), 2 had refractory anemia with excess of blasts (RAEB), 1 had RAEB in transformation (RAEB-t), and 2 had chronic myelomonocytic leukemia (CMMoL) according to the French-American-British (FAB) Cooperative Group criteria. The chromosome 11 abnormalities comprised trisomy 11 (2 patients), monosomy 11 (1 patient), del(11)(q23) (2 patients), add(11)(p15) (1 patient), and der(11) t(3;11)(p21;q23) (1 patient). Abnormalities involving band q23 of chromosome 11 occurred in 3 cases and were the most common alteration. However, specific chromosomal alterations were not associated with any FAB classification group. These findings and their implications in the biology of MDS are discussed.

Clinical aspects, cytogenetics and disease evolution in myelodysplastic syndromes

Myelodysplastic syndrome (MDS) is a morphologically characterized hematologic entity that is one of the clonal myeloproliferative disorders. Approximately 50 approximately 70% of MDS patients have cytogenetic abnormalities; these are usually chromosomal deletions, but some involve translocations such as t(1;7) (q10;p10). Translocations involving chromosomal regions 3q26 or 22q11 are often therapy-related. Recent studies have demonstrated that cytogenetic changes in MDS patients have clinical relevance. Accordingly, there are now scoring systems for predicting the prognoses of MDS patients. In this review, we describe the clinical significance of cytogenetic changes in MDS. We include MDS with some atypical forms, such as MDS with hypocellular bone marrow, MDS with minimal dysplasia, and MDS with myelofibrosis.

Diagnostic and prognostic significance of cytogenetics in adult primary myelodysplastic syndromes

Cytogenetic analysis has proven to be a mandatory part of the diagnosis of myelodysplastic syndromes (MDS) as well as a major indicator for predicting clinical course and outcome. This review concentrates on the cytogenetic classifications, the incidence and types of chromosome defects and the prognostic significance of the karyotype in adult primary MDS. Two cytogenetic classifications are currently used: one is based on the karyotype complexity (normal, single, double or complex defects), the other on clonal status (all metaphases normal, abnormal or admixture of normal and abnormal clones). Chromosome abnormalities are of both numerical and structural types. Aside from the 5q-syndrome, no specific clinico-cytogenetic entity has been reported. However, several distinct clinical and cellular features have been identified that correlate with the presence of specific chromosome defects such as inv(3)/t(3;3), +6, t(5;12), del(17p) and del(20q). The presence of complex defects is associated with reduced survival and a high risk of leukemic transformation. Among single defects, specific abnormalities may define distinct prognostic groups. Patients with del(5q) as a sole chromosome defect and a refractory anemia without excess of blasts have a favourable prognosis. For patients with trisomy 8 or monosomy 7 there may be distinct types of clinical evolution. Most patients with the 3q21q26 syndrome have a short survival. The presence of two chromosome defects may constitute an independent cytogenetic entity probably associated with relative poor prognosis. Karyotypic evolution generally represents a poor risk factor. The combination of cytogenetics with clinical and hematological features has proven to provide for a better prediction of patients' survival, leukemic transformation and response to treatment. Several scoring systems have been developed. They have to be improved by the study of new patients according to strict clinical and cytogenetic criteria and by the addition of newly recognized prognostic indicators such as histopathological features and molecular genetic mutations.

Hematologic, clinical, and cytogenetic analysis in 109 patients with primary myelodysplastic syndrome. Prognostic significance of morphology and chromosome findings

One hundred and nine patients with primary myelodysplastic syndrome (MDS) were classified according to the French-American-British (FAB) criteria: 27 refractory anemia (RA, 25%), 26 RA with ringed sideroblasts (RARS, 24%), 16 RA with excess of blasts (RAEB, 15%), 10 RAEB in transformation (RAEB-t, 9%), 25 chronic myelomonocytic leukemia (CMMoL, 23%), and five unclassifiable MDS (4%). Forty-three were women and 66 were men (sex ratio 2:3). Age ranged from 30-92 years (mean 69 years) with nine patients aged less than 50 years (8%). A cytogenetic result was obtained in all cases. At initial study, a chromosome defect was observed in 56% of patients. Rates of abnormality depended on FAB subtype: 52% in RA, 100% in RA 5q-, 50% in RARS, 56% in RAEB, 70% in RAEB-t and 44% in CMMoL. The most frequent single defects were del(5q), -7/del(7q), del(20q), Y loss, and +8. Except for the 5q- syndrome entity, specific chromosome defects were not associated with particular FAB subtypes. Bone marrow (BM) insufficiency (22%) and leukemic transformation (21%) were the most important causes of death. The rate of leukemic transformation increased with the number of dysplastic BM cell lineages and was also associated with karyotype complexity and the proportion of abnormal/normal metaphases. The longest median survivals were observed in RARS (142 months) and RA/RA5q- (91 months) types. Median survivals decreased with increasing Bournemouth score values. Patients with three abnormal cell lineages had a median survival shorter than those with one or two abnormal lineages. Similarly, patients with complex defects had shorter survival than those with single or double defects or a normal karyotype. There was no statistically significant difference between survival of NN (normal), AN (abnormal/normal), and AA patients or between survival of patients with del(5q), -7/del(7q), +8 or del(20q).

De novo myelodysplastic syndrome (MDS) with deletion of the long arm of chromosome 20: a subtype of MDS with distinct hematological and prognostic features?

We report on 8 cases of de novo myelodysplastic syndromes (MDS) with deletion of the long arm of chromosome 20 (del 20q), who represented about 2% (8/392) of our cases of de novo MDS with cytogenetic analysis seen during a period of 9 yr. Median age was 69 yr, and there were 7 males and 1 female. Anemia was absent or very mild (Hb > 11 g/dl) in 5 patients. Only 1 patient had neutrophils < 0.5 x 10(9)/l, and none had platelets < 50 x 10(9)/l. Four patients had refractory anemia (RA), 2 had refractory anemia with ringed sideroblasts (RARS), and 2 had refractory anemia with excess of blasts (RAEB). Del 20q was isolated in 5 patients, and associated with other chromosomal rearrangement(s) in 3 patients. Only 1 patient progressed to ANLL and 2 showed an increase in bone marrow blasts during evolution. The 5 other patients had stable disease after 18-77 months. By comparison with de novo MDS patients with other cytogenetic findings, patients with del 20q had a tendency towards lower incidence of anemia and excess of marrow blasts, lower incidence of progression to AML and more prolonged survival, although differences were not significant. Only patients with isolated del 5q had a more prolonged survival than patients with del 20q.

Karyotypic analysis in primary myelodysplastic syndromes

Cytogenetics has provided new insights into the biology and pathogenesis of myelodysplastic syndromes. In patients with refractory anemia, it has provided proof of clonality and has helped differentiate chronic myelomonocytic leukemia from chronic myeloid leukemia. As a prognostic tool, cytogenetics has been predictive of duration of survival and leukemic transformation. However, its role as an independent prognostic factor compared with recent prognostic scoring systems remains to be determined. New techniques such as fluorescent in situ hybridization using chromosome-specific DNA probes may expand the usefulness of cytogenetics. The prognostic impact of cytogenetics may not be fully realized until more effective treatments become available.