AML and MDS

Question 1

Different types of AML are diagnosed according to WHO criteria - what do these take into account?

Answer 1

• Morphology
• Immunophenotype
• Cytogenetics
• Molecular findings

Question 2

What are the three major subtypes of AML by the WHO sub-classification?

Answer 2

1. AML with recurrent cytogenetic abnormalities
2. AML with multi lineage dysplasia (following MDS/MPD or with dysplasia in more than 50% of cells in two lineages)
3. AML-NOS (classified morphologically)

Question 3

What are the difference cytogenetic risk groups in AML?

Answer 3

• Favourable survival = Balanced trans
• Intermediate survival = Normal karyotype and everything that doesn’t fit into good/poor risk
• Adverse survival = Complex karyotypes (-5, -7 etc)

Question 4

What are three common acquired abnormalities used for diagnosis of AML? What is their risk?

Answer 4

• t(15;17) in APML
• t(8;21) in core binding factor AML
• inv(16) in CBF AML
• All three fall into the favourable risk group

Question 4

Provide details on 3 balanced translocations seen in AML

Answer 4

• t(8;21)(RUNXT1/RUNX1) and inv16 (CBFB/MYH11) generate chimeric proteins of the core binding factor family that orchestrate cellular transcription
• t(15;17) is cause of APML and the chimeric PML-RARa protein blocks cellular differentiation

Question 5

What are some of the purposes of cytogenetic testing in myeloid malignancies?

Answer 5

• Diagnosis
• Prognosis
• Monitoring: Response to treatment, remission/relapse status, loss/return of abnormalities seen at diagnosis, post-BMT look for recipient/donor cells

Question 7

APML is treated very successfully with what?

Answer 7

ATRA (retinoic acid) and arsenic

Question 8

What type of PCR can be used to detect balanced translocations in diseases such as AML?

Answer 8

Nested reverse transcriptase PCR

Question 9

What two mutations are routinely assayed for in AML?

Answer 9

• FLT3 (receptor tyrosine kinase)

- NPM (nucleophosmin shuttling protein)

Question 10

Provide some details on FLT3 mutations in AML

Answer 10

• internal tandem duplications confer a poor prognosis (20-30% of cytogenetically normal AML)
• point mutations (e.g. D835) also occur but clinical impact is less clear (~7% of AML)

Question 11

Provide some details on NPM mutations in AML

Answer 11

• Mutations in this gene result in the encoded protein being re-localised from the nucleus to the cytoplasm
• These confer a favourable prognosis
• 50-60% freq in cytogenetically normal AML

Question 12

What assay can be used for both FLT3 internal tandem duplications and NPM1?

Answer 12

• Both are insertion polymorphisms

- can therefore be assayed using fragment analysis on an agarose gel or genetic analyser

Question 13

What is qPCR used for in the context of diseases such as AML?

Answer 13

sequential monitoring of minimum residual disease to predict relapse

Question 14

Isocitrate dehydrogenase mutations have been found in AML - provide some details

Answer 14

• IDH is a metabolic enzyme which mediated epigenetic modification of DNA
• Mutations in IDH generate novel protein with enhanced effect on global methylation

Question 15

What is the future of mutation testing in AML?

Answer 15

NGS gene chip looking at a number of genes relevant to the disease

Question 16

Describe some key features of myelodysplastic syndromes

Answer 16

• Dysplasia in one or more myeloid precursors
• Ineffective haematopoiesis
• Increased apoptosis
• Peripheral cytopenia (anaemia, neutropenia, thrombocytopenia)
• May be indolent or aggressive
• Variable tendency to transform into AML

Question 17

Over 80% of MDS patients will have what type of genetic abnormality?

Answer 17

• Somatic gene mutation
• Mutated genes involved in wide range of oncogenic and biologically important pathways including epigenetics, transcription, splicing etc.

Question 18

What are the abnormality risk groups associated with myelodysplastic syndrome (MDS)?

Answer 18

• Good: normal, minus Y, del(5q), del(20q)
• intermediate: other abnormalities
• Poor: complex (more than 3 anomalies) or chr7 anomalies