Leukaemia Flashcards
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?
- Irradiation
- 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