Acute Leukaemia Flashcards

1
Q

What are signs and symptoms of acute leukaemia?

A

Rapid onset

Early death if untreated

Immature cells (blast cells)

Bone marrow failure:

  • Anaemia: Fatigue, pallor, breathlessness
  • Neutropenia: Infections
  • Thrombocytopenia: Bleeding
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2
Q

What are features of acute myeloid leukaemia?

A

Increases with age

Prognosis worse with increasing age

40% of adults cured

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3
Q

Which chromosomal translocations are associated with acute myeloid leukaemia?

A

t(15;17)

t(5;8)

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4
Q

Which chromosomal inversion is associated with acute myeloid leukaemia?

A

A chromosomal inversion, inv(16)

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5
Q

What is the association between chromosomal duplication and AML?

A

Common in AML

Disease hotspots: +8 and +21 give predisposition

Possible dosage affect – extra copies of proto-oncogenes

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6
Q

What is the association between chromosomal loss or deletion and AML?

A

Common in AML

Disease hotspots: Deletions and loss of 5/5q & 7/7q

Possible loss of tumour suppressor genes.

Alternative explanation ‒ one copy of an allele may be insufficient for normal haemopoiesis. Possible loss of DNA repair systems.

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7
Q

What are the molecular abnormalities in patients with apparently normal chromosomes which can result in AML?

A

Point mutation: NPM1, CEBPA

Loss of tumour suppressor genes

Partial duplication: FLT3

Cryptic deletion

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8
Q

What are risk factors for AML?

A

Familial or constitutional predisposition

Irradiation

Anticancer drugs

Cigarette smoking

Unknown

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9
Q

What is leukaemogenesis in AML?

A

Multiple genetic hits

At least 2 interacting molecular defects

Synergise to give leukaemic phenotype

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10
Q

What are the two types of abnormalities in leukaemogenesis in AML?

A

Type 1 abnormalities: Promote proliferation and survival.

Type 2 abnormalities: Block differentiation (which would normally be followed by apoptosis).

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11
Q

How is differentiation affected in AML?

A

Transcription factors:

  • Bind to DNA
  • Alter structure to favour transcription
  • Regulate gene expression

If transcription factor function is disrupted, cells cannot differentiate.

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12
Q

What can be seen in t(8,21) AML?

A

With this particular chromosomal abnormality there is some maturation; these are not all blast cells.

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13
Q

What can be see in inv(16), t(16;16) AML?

A

In this genetic subtype there is some maturation to bizarre eosinophil precursors with giant purple granules.

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14
Q

What can be seen in acute promyelocytic leukaemia with t(15;17)?

A

A very special type of acute leukaemia.

The molecular mechanism is understood, thus molecular treatment can be applied. The great majority of patients can now be cured.

An excess of abnormal promyelocytes.

Disseminated intravascular coagulation (DIC).

Two morphological variants but the same disease.

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15
Q

What are the two types of abnormalities in acute promyelocytic leukaemia?

A

Type 1 abnormalities: FLT3 -ITD

Type 2 abnormalities: t(15;17) PML-RARA

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16
Q

What are abnormalities in leukaemogenesis in CBF leukaemias?

A

Type 1 abnormalities: Sometimes mutated KIT

Type 2 abnormalities: Mutation affecting function of CBF

17
Q

What is the difference between cytochemistry between AML and ALL?

A

AML: Myeloperoxidase, Sudan black, Non-specific esterase positive

ALL: Negative

18
Q

What can be used if cytochemistry does not differentiate between AML and ALL?

A

Immunophenotyping:

  • Cell surface and cytoplasmic antigens
  • Flow cytometry
  • Immunocytochemistry
  • Immunohistochemistry
19
Q

What immunophenotypes are associated with ALL?

A

Precursor-B-cell: CD19, CD20, TdT, CD10 +/-

B-cell: CD19, CD20, surface Ig

T-cell: CD2, CD3, CD4, CD8,TdT

20
Q

What immunophenotypes are associated with AML?

A

MPO, CD13, CD33, CD14, CD15, glycophorin (E), platelet antigens

21
Q

What immunophenotypes are associated with both ALL and AML?

A

CD34, CD45, HLA-DR

22
Q

What are clinical features of AML?

A

Bone marrow failure:

  • Anaemia
  • Neutropenia
  • Thrombocytopenia

Local infiltration:

  • Splenomegaly
  • Hepatomegaly
  • Gum infiltration (if monocytic)
  • Lymphadenopathy (only occasionally)
  • Skin, CNS or other sites
23
Q

How is AML diagnosed?

A

Blood film:

  • Usually diagnostic: circulating blasts
  • Auer rods (proves myeloid)
  • “Aleukaemic” leukaemia: If there are no leukaemic cells in in the blood you need a bone marrow aspirate.
24
Q

What is ALL?

A

Peak incidence in childhood.

Most common childhood malignancy.

85% of children cured.

Prognosis worse with increasing age.

25
Q

What are clinical features of ALL?

A

Bone marrow failure:

  • Anaemia
  • Neutropenia
  • Thrombocytopenia

Local infiltration:

  • Lymphadenopathy (± thymic enlargement)
  • Splenomegaly
  • Hepatomegaly
  • Testes, CNS, kidneys or other sites
  • Bone (causing pain)
26
Q

What are the pathological features of ALL?

A

Peripheral blood:

  • Anaemia
  • Neutropenia
  • Thrombocytopenia
  • Usually lymphoblasts

Bone marrow and other tissues:

  • Lymphoblast infiltration
  • Lymphoblasts may be B-lineage or T-lineage
27
Q

How do the genetic factors contribute to the prognosis of ALL?

A

As for AML, prognosis is very dependent on cytogenetic/genetic subgroups, particularly for B-lineage ALL.

  • Hyperdiploidy, t(12;21), t(1;19) — good prognosis
  • t(4;11), hypodiploidy — poor prognosis
  • t(9;22) — improved prognosis with tyrosine kinase inhibitors
28
Q

What are the leukaeomogenic mechanisms of ALL?

A

Proto-oncogene dysregulation – chromosomal translocation

Fusion genes

Wrong gene promoter

Dysregulation by proximity to T-cell receptor (TCR) or immunoglobulin heavy chain loci

Unknown – hyperdiploidy

29
Q

How is ALL diagnosed?

A

Clinical suspicion

Blood count and film

Bone marrow aspirate

Immunophenotyping

Cytogenetic/molecular genetic analysis

Blood group, LFTs, creatinine, electrolytes, calcium, phosphate, uric acid, coagulation screen