Haematology 2: Acute Leukaemias Flashcards

1
Q

Which acute leukaemia is an emergency ?

A

APML

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2
Q

What translocation causes Acute promyelocytic leukaemia (APML) ?

A

T(15;17) (PML-RARA)

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3
Q

Which leukaemia is more common in patients with Down’s syndrome ?

A

AML

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4
Q

What signs is characteristic in APML ?

A

Sudden onset Haemorrhage (bruising and bleeding)

DIC + Hyperfibrinolysis

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5
Q

Which feature is characteristic of APML on microscopy ?

A

Multiple auer rods

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6
Q

What does the variant of APML without auer rods look like on microscopy ?

A

Promyelocytes with Bilobed nuclei

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7
Q

Which 2 stains are possitive in AML but not In ALL ?

A

Myeloperoxidase stain

Sudan black B stain

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8
Q

Which anaemia causes Gum infiltration ?

A

Monocytic AML

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9
Q

List 5 signs of AML ?

A

Anaemia- SOB, Pallor
Neutropenia- infections
Thrombocytopenia- easy bruising and bleeding, petichiae, ecchymoses, DIC
Local infiltration - hepatosplenomegaly, gum infiltration, lymphadenopathy, skin, CNS
Hyperviscocity if WBC is high

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10
Q

What is the most important diagnostic test for Leukaemias ?

A

Immunophenotyping

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11
Q

What is the most common leukaemia in childhood ?

A

ALL

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12
Q

List 5 signs of ALL ?

A
Anaemia- SOB, pallor  
Neutropenia- infections
Thrombocytopenia- Easy bruising, bleeding
Lymphadenopathy 
Hepatosplenomegaly
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13
Q

Which drug is used to treat CML or ALL with the Philadelphia chromosome abnormality ?

A

Tyrosine kinase inhibitor- Imatinib

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14
Q

list features of acute laeukaemia

A

rapid onset
early death if untreated
immature cells (blasts)
bone marrow failure - anaemia, thrombocytopenia, neutropaenia

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15
Q

features of AML

A

incidence increases with age
many AMLs have aberrations in chromosome count or structure
abberations are recurrent

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16
Q

what types of chromosomal abnormalities are seen in AML

A
duplication 
loss
translocation - t(15;17) in APML (acute promyelocytic leukaemia
inversion 
deletion
altered DNA sequence
17
Q

what chromosomes are commonly duplicated in AML

A

+8 and +21 (predisposition as seen in Down’s syndrome)

18
Q

what chromosomal losses are common in AML

A

deletion or loss of 5/5q or 7/7q

  • may be a loss of a tumour suppressor gene
  • one copy of an allele may be insufficient for normal haemopoiesis
  • loss of DNA repair systems
19
Q

what molecular abnormalities may be present in someone with apparently normal chromosomes in AML

A

point mutations - NPM1, CEBPA
loss of function of TS genes
partial duplication
cryptic deletion

20
Q

risk factors for AML

A

familial or constitutional predisposition ( Down syndrome)
irradiation
anticancer drugs
cigarettes

21
Q

describe leukaemogenesis in AML

A

need multiple genetic hits
type 1 abnormalities - promote proliferation and survival (anti-apoptosis)
type 2 abnormalities - block differentiation - accumulation of blast cells
differentiation - disruption of TF function

22
Q

describe how a translocation in core binding factor can lead to AML

A

CBF = dimeric TF
translocation 8;21 fuses RUNX + RUNX1T1
fusion transcription factor formed
drives leukaemia by causing a differentiation block

23
Q

describe how an inversion of chromosome 16 can cause AML

A

inv (16,) t(16;16)

the inversion fuses CBF-beta to MYH11 to form a fusion product that cannon bind DNA sequence - arrests differentiation

24
Q

what is APML

A

acute promyelocytic leukaemia
causes haemorrhage (acute onset bruising and bleeding)
excess abnormal promyelocytes
characterised by DIC and hyperactive fibrinolysis
two morphological variants
translocation chr 15 + 17
= PML-RARA fusion gene
the promyelocytes are abnormal because they contain multiple AUER RODS
variant form - bilobed nuclei

25
Q
summarise leukaemogenesis in AML...
--- --- dysregulation is important 
but not -- to cause leukaemia
further genetic hits required 
-- and -- encouraged 
-- is blocked
A
transcription factor dysregulation is important 
but not sufficient to cause leukaemia
further genetic hits required 
proliferation and survival encouraged 
differentiation is blocked
26
Q

cytological features of AML

A

fine speckled granules

auer rods

27
Q

cytochemistry for AML

A

stain for myeloperoxidase

28
Q

immunophenotyping for AML

A
looking at antigens on the cell surface/within the cytoplasm 
done by:
- flow cytometry 
- immunocytochemistry 
- immunohistochemistry
29
Q

how is AML diagnoses

A

blood film - auer rods, immunophenotyping,
bone marow aspirate
cytogenetic studies t(15;17), t(8;21), inv (16)/t(16;16)
FISH studies

30
Q

treatment of AML

A

supportive care - red cells, platelets, FFP/cryoprecipitate, antibiotics, allopurinol
chemo - combination (6 months)
transplantation if poor prognosis

31
Q

describe features of ALL

A

peak in childhood
85% children cured
most common childhood malignancy
prognosis worse with increasing age

32
Q

clinical features of ALL

A
BM infiltration 
local infiltration:
- lymphadenopathy +/- thymic enlargement 
- splenomegaly 
- hepatomegaly 
- testes, CNS, kidneys, other sites 
- bone
33
Q

ALL on blood film

A

anaemia
neutropenia
thrombocytopenia
usually lymphoblasts

34
Q

what genetic features give a good prognosis for ALL

A

hyperdiploidy
T(12;21)
T(1,9)

35
Q

what genetic factors give a poor prognosis in ALL

A

T(4;11)

hypodiploidy

36
Q

what gives a good prognosis with tyrosine kinase inhibitors in ALL

A

T(9;22) - philodelphia chromosome

usually in CML but rarely in ALL

37
Q

describe leukaemogenic mechanisms in ALL

A
proto-oncogene dysreg
- chromosomal translocations
- fusion genes
- wrong gene promoter 
hyperdiploidy
38
Q

how is ALL diagnosed

A
clinical suspicion
blood count and film 
BM aspirate
immunophenotyping 
cytogenetic/molecular genetic analysis
39
Q

how is ALL treated

A

systemic chemotherapy - 2-3 years, boys need longer
CNS-directed therapy - eg intrathecal

supportive:
blood products
antibiotics - prophylaxis against PCP