Leukaemia Flashcards
What is leukaemia?
Neoplasm or cancer arising as a result of mutation in a precursor of myeloid or lymphoid cells
What is the difference between lymphoid and myeloid leukaemia?
Differentiate by cell of origin
Lymphoid = B or T lineage
Myeloid = any combination of granulocytic, monocytic, erythroid or megakaryocytic
What is the difference between acute and chronic leukaemia?
Acute = if untreated, has profound pathological effects and leads to death in a matter of days, weeks or months Chronic = causes less impairment of function of normal tissues and, although it will eventually lead to death, this usually does not occur for a number of years
What are the clinical features of acute lymphoblastic leukaemia?
Resulting from accumulation of abnormal cells:
- Bone pain
- Hepatomegaly
- Splenomegaly
- Lymphadenopathy
- Thymic enlargement
- Testicular enlargement
Resulting from crowding out of normal cells:
- Fatigue, lethargy, pallor, breathlessness (caused by anaemia)
- Fever and other features of infection (caused by neutropenia)
- Bruising, petechiae, bleeding (caused by thrombocytopenia)
What are the haematological features of acute lymphoblastic leukaemia?
- Leucocytosis with lymphoblasts in blood
- Anaemia (normocytic, normochromic)
- Neutropenia
- Thrombocytopenia
- Replacement of normal BM cells by lymphoblasts
What are the genetic features of acute lymphoblastic leukaemia?
ALL results from mutation in a T- or B-lineage lymphoid stem cell
Mutations in proto-oncogenes:
- Point mutations
- Internal tandem duplication of parts of genes
- Formation of fusion genes
- Dysregulation when a gene comes under control of promoter/enhancer of another gene during translocation
- Somatic hypermutation subsequent to a translocation
Gene expression may be abnormal as result of demethylation
Sometimes mutation of TSG
What kind can happen to a TSG to cause leukaemia?
- Deletion of gene
- Inactivation through mutation
