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Y2 MCD - Cancer - Laz > Leukaemia > Flashcards

Flashcards in Leukaemia Deck (33)
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What is the most common cancer in the 15-24 age group?

Cancers of the blood


What is the literal meaning of leukaemia?

White blood


Where does the problem exist in leukaemia?

In the bone marrow (not all patients have abnormal cells in the blood)


What does leukaemia result from?

A series of mutations in a single lymphoid or myeloid stem cell


What are the consequences to the progeny of the mutated cell?

These mutations lead to progeny of that cell to show abnormalities in proliferation, differentiation or cell survival leading to steady expansion of the leukaemic clone


Which cells can be affected in leukaemia?

Pluripotent haematopoietic stem cell
Myeloid stem cell
Lymphoid stem cell
Pre B lymphocyte
Pro T lymphocyte


What are the equivalent terms for ‘benign’ and ‘malignant’ in terms of leukaemia?

Leukaemias that behave relatively benignly are CHRONIC
Leukaemias that behave in a malignant manner are ACUTE– the disease is very aggressive


What are the four main types of leukaemia?

Acute lymphoblastic leukaemia
Acute myeloid leukaemia
Chronic lymphocytic leukaemia
Chronic myeloid leukaemia


Explain the significance of the terms acute lymphoblastic leukaemia and chronic lymphocytic leukaemia.

In ALL the cells are immature – they are lymphoblasts
IN CLL the cells are mature lymphocytes


What are the important leukaemogenic mutations that have been recognised?

Mutation in a known proto-oncogene
Creation of a novel gene e.g. chimeric or fusion gene
Dysregulation of a gene when translocation brings it under the influence of a promoter or enhancer of another gene


State some inherited or other constitutional abnormalities that can contribute to leukaemogenesis.

Down syndrome
Chromosomal fragility syndromes
Defects in DNA repair
Inherited defects in tumour suppressor genes


What are some identifiable causes of leukaemogenic mutations?

Anti-cancer drug
Cigarette smoking
Chemicals e.g. benzene


What type of cell is seen in abundance in acute myeloid leukaemia?

Immature myeloid cells – the cells continue to proliferate but they no longer mature so there is a build up of immature cells (myeloblasts) in the bone marrow, which spread to the blood


Explain how acute leukaemia leads to bone marrow failure.

The leukaemic cells crowd out the normal cells in the bone marrow leading to a decrease in the production of other end cells e.g. neutrophils, monocytes, platelets


What do the responsible mutations normally affect in AML?

Transcription factors – the transcription of multiple genes is affected
Often the product of an oncogene prevents the normal function of theprotein encoded by its normal homologue
This leads to changes in cell kinetics and cell functions


What do the responsible mutations normally affect in CML?

A gene encoding a protein in the signalling pathway between a cell surface receptor and the nucleus
The protein encoded may be a membrane receptor or a cytoplasmic protein


Describe the nature of the leukaemic cells in CML.

These are mature lymphocytes – their cell kinetics and function are not as seriously affected as they are in AML but the cells do become independent of external signals, there are alterations in the interaction with stroma and there is reduced apoptosis so that cells survive longer and the leukaemic clone expands progressively


How is the production of end cells affected in AML and CML?

AML – decrease in the production of end cells
CML – increase in the production of end cells


What are the metabolic effects of leukaemic cell proliferation?

Renal failure
Weight loss
Low grade fever


Which type of leukaemia increases the risk of intraventricular haemorrhage and why?

Acute promyelocytic leukaemia (APML) – this is associated with DIC so the platelet count and fibrinogen are low leading to increased risk of fatal haemorrhage


How can leukaemia cause proliferation of the gums?

Infiltration of leukaemic cells and monocytes can lead to inflammation of the gums
There will be small haemorrhages due to thrombocytopenia


What does epidemiology suggest that B lineage acute lymphoblastic leukaemia may result from?

It may result from delayed exposure to a common pathogen


What are some factors that relate to risk of leukaemia?

Family size, new towns, socio-economic class, early social interactions


What can leukaemias in infants and young children result from?

Irradiation in utero
In utero exposure to certain chemicals


What are the clinical features of acute lymphoblastic leukaemia?

Bone pain
Thymic enlargement
Testicular enlargement
These all result from the accumulation of abnormal cells


What are some clinical features of acute lymphoblastic leukaemia that result from the crowding out of normal cells

Caused by anaemia – fatigue, lethargy, pallor, breathlessness
Caused by neutropenia – fever and other features of infection
Caused by thrombocytopenia – bruising, petechiae, bleeding


What investigations are performed in acute lymphoblastic leukaemia?

Blood count and film
Check of liver function and renal function and uric acid
Bone marrow aspirate
Cytogenetic/molecular analysis
Chest X-ray


What are the uses of cytogenetic and molecular genetic analysis in ALL?

It is useful for managing the individual patient because it gives us information about prognosis
It permits the discovery of leukaemogenic mechanisms


What are the implications of hyperdiploidy in in the cytogenetic analysis of ALL?

Good prognosis


What features of the cytogenetic analysis are associated with a poor prognosis?

Chromosomal translocations resulting in the formation of a bad fusion gene