Myelodysplastic Syndromes

Primary Author South, Sarah T., PhD.

Key Points

Cytogenetic Testing for Myelodysplastic Syndromes (MDS)

Cytogenetic studies play a key role in the evaluation of patients with MDS; results are used to establish a diagnosis, stratify patients into prognostic groups, guide medical management, and monitor disease progression. Clonal abnormalities are observed in approximately 50% of cases evaluated by metaphase cytogenetic analysis and in up to 80% of cases evaluated by cytogenomic single nucleotide polymorphism (SNP) microarray.

The following patients may still have clonal genetic abnormalities that can be detected by cytogenomic SNP microarray: normal karyotype, suboptimal (<20) normal metaphases, or growth failure result from metaphase chromosome study. Cytogenomic SNP microarray testing can detect both copy-number alteration (loss or gain of DNA) and copy-neutral loss of heterozygosity (LOH), which is often due to mutations and subsequent selection of mutant tumor-suppressor genes and oncogenes. In addition, many copy-number alterations identified by cytogenomic SNP microarray may be monitored by FISH.

  • Conventional cytogenetics, FISH, and cytogenomic SNP microarray testing comparisons
Conventional Cytogenetics (Karyotype)Fluorescence in situ Hybridization (FISH)Cytogenomic Microarray Testing
Suggested Use
Diagnosis, prognosis, and monitoring of minimal residual disease (MRD)

May increase diagnostic sensitivity in MDS if metaphase cytogenetic study is suboptimal (<20 normal metaphases) or fails

Use to clarify findings from an abnormal karyotype

Use to establish and/or monitor for abnormal clone

Complements conventional cytogenetic methods and leads to a comprehensive cytogenetic characterization of MDS

Detects copy number alterations (loss/gain of DNA) and loss of heterozygosity (LOH)

Only method that can identify MDS-associated LOH (eg, uniparental disomies like UPD7q, UPD11q and UPD17p)

Preferred test for MDS patients with a normal karyotype, suboptimal metaphase cytogenetics (<20 normal metaphases), or failed metaphase cytogenetic study

Limitations

G-banded metaphase chromosome analysis has limited resolution. This technique may fail to identify subtle abnormalities and cannot identify cryptic (sequence-level) alterations or LOH. Complex rearrangements or uncertainty of additional genomic material may require further clarification by molecular methods

Success rate dependent upon growth of tumor cells in culture

FISH using standard MDS panels is unlikely to increase diagnostic sensitivity if a complete (20-cell) metaphase cytogenetic study is normal

FISH analysis is a targeted molecular cytogenetic method and chromosome alterations outside probe region are not detected

 Cannot detect LOH

This technology will detect only copy-number alterations and LOH

This technology cannot detect balanced genomic rearrangements such as translocations, inversions, or balanced insertions and may not detect low-level mosaicism (<15-20%)

ARUP Tests

Chromosome Analysis, Bone Marrow with Reflex to Genomic Microarray 2007130

Chromosome Analysis, Bone Marrow 2002292

Myelodysplastic Syndrome (MDS) Panel by FISH 2002709

Acute Myelogenous Leukemia (AML) with Myelodysplastic Syndrome (MDS), or Therapy-Related AML, by FISH 2002653

Cytogenomic SNP Microarray-Oncology  2006325

Cytogenomic Molecular Inversion Probe Array, FFPE Tissue – Oncology 2010229

 Cazzala M et al, 2011; Shih AH, 2011; Simons A, 2012;  Tiu RV, 2011; Coleman JF, 2011

Diagnosis

Indications for Testing

  • Abnormal CBC or peripheral smear in the absence of obvious etiology – cytopenias and dysplastic cells in peripheral smear are most common

Criteria for Diagnosis

  • MDS – International Consensus Working Group (2007) recommendations
    • Stable cytopenia for >6 months
      • Only 2 months required if accompanied by specific karyotype or bilineage dysplasia
    • Exclusion of other potential disorders as a primary reason for dysplasia or cytopenia
    • At least one MDS-related (decisive) criterion
      • Unequivocal dysplasia (≥10% in ≥1 of the 3 major bone marrow lineages)
      • Blast cell count of 5-19%
      • Specific MDS-associated karyotype [eg, del(5q), del(20q), +8, -7/del(7q)]
    • Co-criteria help confirm the diagnosis
      • Bone marrow histology and immunohistochemistry to detect fibrosis, dysplastic megakaryocytes, atypical localization of immature progenitors
      • Flow cytometric analysis to identify abnormal myeloid antigen patterns, abnormal CD34 expression in blasts
      • Molecular markers to detect myeloid clonality
  • Presumptive MDS – this diagnosis is for individuals with refractory cytopenia(s) who lack unequivocal dysplasia if specific cytogenetic abnormalities are detected
  • AML with myelodysplasia-related changes
    • >20% blood or marrow blasts AND previous history of MDS or MDS-related cytogenetic abnormality OR multilineage dysplasia
      • Dysplasia in at least 50% of cells in 2 or more hematopoietic lineages
    • Absence of cytogenetic abnormalities described in AML with recurrent genetic abnormalities
    • No history of prior cytotoxic therapy for an unrelated disease
  • Therapy-related myeloid neoplasms (t-MDS, t-MDS/MPN, or t-AML)
    • Myeloid neoplasms (excluding MPNs) that arise as a consequence of cytotoxic or radiation therapy
    • May be subdivided by blast count but behave as a single biologic disease

Histology

  • Classification based on peripheral smear, bone marrow histology, and cytogenetic testing
    • Bone marrow biopsy – diagnosis almost exclusively made using marrow appearance
      • Criteria – dysplasia in ≥10% of myeloid lineage cells
    • Cytogenetic testing – evaluate for recurrent chromosome abnormalities consistent with MDS
      • FISH – does not add substantially for diagnosis in cytogenetically normal cases
      • Microarray – identification of MDS-associated imbalances and loss of heterozygosity in ~20% of cases with normal cytogenetic chromosome analysis
      • Most common abnormalities – del(5q) and del(7q), trisomy
    • Flow cytometry
      • Changes not specific for MDS; may be most useful in ruling out other neoplasms associated with cytopenias
      • Absence of  flow cytometric abnormalities does not exclude MDS
    • Immunohistochemistry – CD117 (c-Kit); CD34 (QBEnd/10); myeloperoxidase (MPO) to identify abnormal localization of immature precursors and increased blasts
  • Refer to Key Points tab for comparisons of FISH, conventional cytogenetics, and cytogenetics SNP microarray for diagnosis

Prognosis

  • Most accurately defined by cytogenetic testing, FISH, and cytogenetic SNP microarray (see Key Points tab)
  • Influenced by karyotype, % blasts, number of cytopenias present, and somatic mutations
  • MDS International Prognostic Scoring System (IPSS)

    IPSS-R Scoring System (2012)

    Prognostic subgroup

    Cytogenetic Abnormality

    Single

    Double

    Complex

    Very Good

    del(11q); -Y

    ------------

    ------------

    Good

    Normal; del(5q); del(12p); del(20q)

    del(5q) combined with another abnormality

    ------------

    Intermediate

    del(7q); +8; i(17q); +19; +21; any other independent clones

    Any other abnormality in combination

    ------------

    Poor

    inv(3)/t(3q)/del(3q); -7

    -7/del(7q) combined with another abnormality

    3 abnormalities

    Very Poor

    ------------

    ------------

    >3 abnormalities

    Greenberg PL, 2012
  • Newest prognostication from WHO classification-based scoring system incorporates transfusion burden
    • Poor prognosis with refractory anemia with excess blasts (RAEB) or refractory anemia with excess blasts in transformation (RAEB-t)
      • Median survival 5-12 months
      • Disease transforms to AML in 40-50%
    • Better prognosis with refractory anemia (RA) or refractory anemia with ring sideroblasts (RARS)
      • Median survival 3-6 years
      • Disease transforms to AML in 5-15%

Differential Diagnosis

Clinical Background

Myelodysplastic syndromes (MDS) are clonal hematopoietic malignancies characterized by ineffective hematopoiesis, cytopenia, unilineage, or multilineage dysplasia, and a susceptibility to leukemia, especially AML.

Epidemiology

  • Incidence  
    • 5/100,000 in the general population (NCCN, 2014)
    • 26-45/100,000 in the elderly population (>70 years) (NCCN, 2014)
  • Age – median is 65-70
  • Sex – M>F

Classification

  • World Health Organization (WHO) classification of MDS (WHO, 2008)

    Subtype

    Blood

    Bone Marrow

    Refractory cytopenias with unilineage dysplasia

    • Refractory anemia
    • Refractory neutropenia
    • Refractory thrombocytopenia
    • Unicytopenia or bicytopenia
    • No or rare blasts (<1%)
    • Unilineage dysplasia ≥10% of one cell line
    • <5% blasts
    • <15% of erythroid precursors ring sideroblasts

    Refractory anemia with ring sideroblasts

    • ≥15% erythroid precursors – ring sideroblasts
    • Erythroid dysplasia only
    •  <5% blasts

    Refractory cytopenia with multilineage dysplasia

    • Cytopenia(s)
    • No or rare blasts (<1%)
    • No Auer rods
    • <1x109/L monocytes
    • Dysplasia in ≥10% of cells in ≥2 myeloid lineages
    •  ±15% ring sideroblasts
    • <5% blasts
    • No Auer rods

    Refractory anemia with excess blasts-1 (RAEB-1)1

    • Cytopenia(s)
    • <5% blasts
    • No Auer rods
    • <1x109/L monocytes
    • Unilineage or multilineage dysplasia
    • No Auer rods
    • 5-9% blasts

    Refractory anemia with excess blasts-2 (RAEB-2)2

    • Cytopenia(s)
    • 5-19% blasts
    • ± Auer rods
    • <1x109/L monocytes
    • Unilineage or multilineage dysplasia
    • ± Auer rods
    • 10-19% blasts

    Myelodysplastic syndrome, unclassified

    • Cytopenia(s)
    • ≤1% blasts
    • Unequivocal dysplasia in <10% of cells in ≥1 myeloid cell lines when accompanied by a cytogenetic abnormality is considered as presumptive evidence for a diagnosis of MDS
    •  <5% blasts

    MDS associated with isolated del(5q)

    • Anemia
    • Platelets normal or increased
    • No or rare blasts (<1%)
    • Normal to increased megakaryocytes with hypolobated nuclei
    • Isolated del(5q) cytogenetic abnormality
    • <5% blasts
    • No Auer rods

    1If marrow myeloblasts <5% but 2-4% myeloblasts in blood = RAEB-1

    2Auer rods and <5% myeloblasts in blood and <10% in marrow = RAEB-2

    Note: NCCN endorses using both the French-American-British (FAB) and WHO classification criteria for RAEB in transformation (RAEB-t) patients

    WHO classification of MDS-myeloproliferative neoplasms (WHO, 2008)

    Subtype

    Blood

    Bone Marrow

    Chronic myelomonocytic leukemia 1

    • >1x109/L monocytes
    • No Philadelphia chromosome or BCR-ABL1 fusion gene
    • <5% blasts
    • Unilineage or multilineage dysplasia
    • <10% blasts

    Chronic myelomonocytic leukemia 2

    • >1x109/L monocytes
    • No Philadelphia chromosome or BCR-ABL1 fusion gene
    • <19% blasts
    • Unilineage or multilineage dysplasia
    • 10-19% blasts

    Myelodysplastic or myeloproliferative disease, unclassifiable

    • Morphological features of MDS
    • Myeloproliferative features with no underlying myeloproliferative disease – platelets >600x109/L; leucocytes >13x109/L; splenomegaly
    • No Philadelphia chromosome or BCR-ABL1 fusion gene
    • No del (5q), t(3;3)(q21;q26), inv3(q21;q26)
     

    Provisional entity (refractory anemia with ring sideroblasts and thrombocytosis)

    • Similar to refractory anemia with ring sideroblasts
    • Platelets >600x109/L
    • Similar to refractory anemia with ring sideroblasts
    • No del(5q)
  • Therapy-related neoplasm (WHO, 2008)
    • AML or MDS in individual exposed to cytotoxic agents

Risk Factors

  • Older age
  • Occupational exposures
    • Benzene-containing products
    • Pesticides
    • Organic solvents
    • Heavy metals (lead, arsenic)
  • Drug exposures
    • Alkylating agents, purine analogues, topoisomerase inhibitors
    • Azathioprine
    • Mycophenolate
  • Radiation
  • Genetic
    • Down syndrome
    • Fanconi anemia
    • Familial myelodysplasia
    • Diamond-Blackfan syndrome

Pathophysiology

  • Clonal expansion of the multipotential hematopoietic cell
  • Primary mechanism is defective maturation of marrow cells coupled with premature cell death

Clinical Presentation

  • MDS
    • May be asymptomatic
      • Disease is generally indolent, with blood counts remaining relatively stable over months or longer
    • Most common symptoms
      • Pallor, weakness, exertional dyspnea – secondary to Anemia  
      • Recurrent infections – secondary to neutropenia
      • Bleeding/bruising – secondary to thrombocytopenia
    • Complications
      • 25-30% progress to AML; incidence depends on MDS subtype
        • Lower response rate to standard therapy for patients >65 years with de novo AML
      • Death from complications of cytopenia (neutropenia in particular)
  • AML with myelodysplasia-related change
    • Elderly individuals predominate
    • Represents 25-30% of AML cases
    • Generally presents with pancytopenia
    • Chromosome abnormalities are similar to those found in MDS unrelated to cytotoxic agents
      • Often involve gain or loss of major segments of specific chromosomes with complex karyotypes
  • Treatment-related myeloid neoplasms
    • Late complication of cytotoxic or radiation therapy
      • Rate of development does not differ between those with a hematologic versus solid malignancy
    • Accounts for 10-20% of all AML, MDS, and MDS/myeloproliferative neoplasms (MPN)
    • 90% have clonal chromosomal abnormality
      • Often complex
      • Similar to those observed in AML with myelodysplasia-related change
    • Disease differs based on type of therapy (alkylating agent/radiation versus topoisomerase II)
      • Individual may have received both therapies at some point during an illness, meaning either presentation can occur
    • t-MDS/t-AML arising after alkylating agent and/or radiation therapy
      • 80–85% of treatment-related myeloid neoplasms
      • Latency period 3-7 years (median 5 years)
      • Initial presentation – MDS with trilineage dysplasia
      • Cytogenetics (most common)
        • Abnormalities of chromosomes 5, 7, or complex karyotypes
    • t-AML/t-MDS arising after topoisomerase II inhibitor therapy
      • ~15% of treatment-related myeloid neoplasms
      • Latency period 2-3 years
      • Initial presentation – AML (typically no antecedent MDS)
      • Cytogenetics
        • Balanced translocations
        • MLL rearrangements
        • t(15;17)
        • inv (16)

Pediatrics

Clinical Background

Epidemiology

  • Incidence – rare; 1-4/million (NCCN, 2014)
  • Age – 6.8 years median

Risk Factors

  • Strongly associated with congenital disorders – evident in 50% of cases
    • Syndromes include
      • Down syndrome
      • Fanconi syndrome
      • Trisomy 8
      • Diamond-Blackfan syndrome
      • Neurofibromatosis type 1
      • Bloom syndrome
      • Noonan syndrome
  • Prior exposure to radiation or chemotherapy

Classification

  • Patients with 2-19% blasts in peripheral blood and/or 5-19% blasts in bone marrow may be classified using the adult schema provisional but exclude patients with Down syndrome
  • Additional pediatric entity of refractory cytopenia of childhood is recognized
    • <2% blasts in peripheral blood and <5% blasts in bone marrow
    • Bilineage dysplasia

Clinical Presentation

  • May be asymptomatic
  • Most common symptoms
    • Anemia – pallor, weakness, exertional dyspnea
    • Hepatomegaly/splenomegaly (5-10%)
    • Arthralgias

Diagnosis

  • Refer to Diagnosis and Key Points tab

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
Chromosome Analysis, Bone Marrow with Reflex to Genomic Microarray 2007130
Method: Giemsa Band/Genomic Microarray (Oligo-SNP array)

Diagnosis, prognosis, and monitoring of MRD in MDS

Reflex pattern – if chromosome analysis is normal or no growth, then genomic microarray testing will be added

Cytogenomic SNP microarray will detect only copy-number alterations and LOH

This technology cannot detect balanced genomic rearrangements such as translocations, inversions, or balanced insertions and may not detect low-level mosaicism (<15-20%)

 
Chromosome Analysis, Bone Marrow 2002292
Method: Giemsa Band

Diagnosis, prognosis, and monitoring of MRD in MDS

This technology cannot detect balanced genomic rearrangements such as translocations, inversions, or balanced insertions and may not detect low-level mosaicism (<15-20%)

 
Chromosome FISH, Interphase 2002298
Method: Fluorescence in situ Hybridization

Use in conjunction with conventional cytogenetics for diagnosis, prognosis and monitoring in MDS and therapy-related myeloid neoplasms

Use to clarify findings from an abnormal karyotype

Use to establish and/or monitor for abnormal clone

Specific FISH probes recommended for this indication include -5/del(5q), -7/del(7q), +8, del20q,  MLL rearrangements (11q23), and EVI1 rearrangements (inv(3) or t(3;3))

ARUP Oncology FISH Probes menu

FISH analysis is a targeted molecular cytogenetic method and chromosome alterations outside probe region are not detected

Limit of detection is probe dependent; approximately 1-5% in interphase nuclei

 
Myelodysplastic Syndrome (MDS) Panel by FISH 2002709
Method: Fluorescence in situ Hybridization

Use to clarify findings from an abnormal karyotype

Use to establish and/or monitor for abnormal clone

May increase diagnostic sensitivity in MDS if metaphase cytogenetic study is suboptimal (<20 normal metaphases) or fails

 Probes include

  • -5/del(5q)
  • -7/del(7q)
  • + 8
  • del(20q)

Each probe can be run as a part of the panel or individually

AML may also include abnormalities detectable by this panel

FISH using standard MDS panels is unlikely to increase diagnostic sensitivity if a complete (20-cell) metaphase cytogenetic study is normal

FISH analysis is a targeted molecular cytogenetic method and chromosome alterations outside probe region are not detected

Limit of detection is probe dependent; approximately 1-5% in interphase nuclei

 
Cytogenomic SNP Microarray - Oncology 2006325
Method: Genomic Microarray (Oligo-SNP Array)

Complements conventional cytogenetic methods and leads to a comprehensive cytogenetic characterization of MDS

Detects copy number alterations (loss/gain of DNA) and LOH

Only method that can identify MDS-associated LOH (eg, uniparental disomies like UPD7q, UPD11q and UPD17p)

Preferred test for MDS patients with a normal karyotype or when metaphase cytogenetics are suboptimal (<20 normal metaphases) or fail

This technology will detect only copy-number alterations and LOH

This technology cannot detect balanced genomic rearrangements such as translocations, inversions, or balanced insertions and may not detect low-level mosaicism (<15-20%)

 
Cytogenomic Molecular Inversion Probe Array, FFPE Tissue - Oncology 2010229
Method: Molecular Inversion Probe Array

Use when only FFPE specimen is available

This technology will detect only copy-number alterations and LOH

This technology cannot detect balanced genomic rearrangements such as translocations, inversions, or balanced insertions and may not detect low-level mosaicism (<15-20%)

 
Acute Myelogenous Leukemia (AML) with Myelodysplastic Syndrome (MDS) or Therapy-Related AML, by FISH 2002653
Method: Fluorescence in situ Hybridization

Use in conjunction with conventional cytogenetics for diagnosis, prognosis, and monitoring of MRD in therapy-related AML/MDS

Use to clarify findings from an abnormal karyotype

Use to establish and/or monitor for abnormal clone

Probes include

  • -5/del(5q)
  • -7/del(7q)
  • 11q23 rearrangements
FISH analysis is a targeted molecular cytogenetic method and chromosome alterations outside probe region are not detected  
CD117 (c-Kit) by Immunohistochemistry 2003806
Method: Immunohistochemistry

Aid in histologic diagnosis of myelodysplastic syndromes; identify abnormal localization of immature precursors and increased blasts

Stained and returned to client pathologist; consultation available if needed

   
CD34, QBEnd/10 by Immunohistochemistry 2003556
Method: Immunohistochemistry

Aid in histologic diagnosis of myelodysplastic syndromes; identify abnormal localization of immature precursors and increased blasts

Stained and returned to client pathologist; consultation available if needed

   
Myeloperoxidase (MPO) by Immunohistochemistry 2004014
Method: Immunohistochemistry

Aid in histologic diagnosis of myelodysplastic syndromes; identify abnormal localization of immature precursors and increased blasts

Stained and returned to client pathologist; consultation available if needed

   
Additional Tests Available
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Chromosome Analysis, Leukemic Blood 2002290
Method: Giemsa Band
Leukemia/Lymphoma Phenotyping by Flow Cytometry 2008003
Method: Flow Cytometry

Aid in evaluation of hematopoietic neoplasms (ie, leukemia, lymphoma)

Monitor therapy in patients with established diagnosis of hematopoietic neoplasms

Specimens include peripheral blood, bone marrow, and tissue

Markers selected based on clinical history, previous flow studies, and pathologist interpretation

Available markers

Myelo/Mono: CD11b, CD13, CD14 (Mo2), CD14 (MY4), CD15, CD33, CD64, CD117, myeloperoxidase

T cell: CD1, CD2, CD3, CD4, CD5, CD7, CD8, TCR alpha-beta, TCR gamma-delta, cytoplasmic CD3

B cell: CD10, CD19, CD20, CD22, CD23, CD103, kappa, lambda, FMC7, cytoplasmic kappa, cytoplasmic lambda

Misc: CD11c, CD16, CD25, CD30, CD34, CD38, CD41, CD42b, CD45, CD56, CD57, CD61, HLA-DR, glycophorin, TdT, bcl-2, ALK-1, CD123, CD138, CD200, CD26, CD45