Blood Cell Abnormalities Flashcards
What is leukaemia?
“White blood”
Bone marrow disease, overspill of abnormal cells into the blood
Arises as a result of mutation in a precursor of myeloid or lymphoid cells
How is leukaemia classified?
Either myeloid or lymphoid
In this case myeloid includes not only granulocytes and monocytes but also megakaryocytes and erythroids
Why is leukaemia slightly different from other types of cancer?
The abnormal cells circulate and spread
Therefore the concepts of local migration and metastasis are difficult to apply
The formation of localised tumour masses is also possible but not necessary
Malignant and benign are not used to describe leukaemias
What terms are used instead of malignant and benign with leukaemia?
Acute and chronic
Depending on the degree of malignancy they shown
Acute : untreated, this would have a profound pathological effect and would cause a quick death
Chronic: less impairment of function of normal tissues. Will eventually lead to death
Determined by the nature of the mutation
What are the fourain types of leukaemia given that there are two categories to consider?
Acute lymphoblastic leukaemia
Acute myeloid leukaemia
Chronic lymphocytic leukaemia
Chronic myeloid leukaemia
Why does leukaemia occur?
A number of mutations in a primitive cell. Gives it a growth advantage
This single cell gives rise to a clone that slowly replaces normal cell
Mutations occur in oncogenes, and sometimes tumour surpressor genes
Are mutations is germ cells (lead to gametes) beneficial or not?
They can be neutral, beneficial or harmful. Beneficial ones allow evolution
Are mutations in somatic cells beneficial or harmful.
Very rarely beneficial. They are usually either neutral or harmful
How do mutations in somatic cells occur?
Could be exposure to mutagens, or a random spontaneous process
The older the person, the more likely it is that enough spontaneous or induced mutations have occurred in a single cell for that cell to expand into a one that replaces normal cells
What is some of the abnormal behaviour displayed by leukaemic clones?
Growth occurring without dependence on growth factors
Continued proliferation without maturation
Failure to undergo normal cell death (apoptosis)
What causes acute lymphoblastic leukaemia?
Usually unowknown, sometimes mutagenic drugs, exposure to irradiation, exposure to chemicals in utero
Possibly delayed exposure to a common pathogen or pathogens
What causes acute lymphoid leukaemia?
Ussually unknown, sometimes irradiation, mutagenic drugs or chemicals
(Benzene, cigarette smoke)
What causes chronic myeloid leukaemia?
Usually unknown
Rarely irradiation or mutagenic drugs
What causes chronic lymphoid leukaemia?
Unknown
Some families are predisposed
What mutations result in acute leukaemias?
Mutations in genes encoding transcription factors with A resultant profound abnormality in the cells ability to mature. However the cells continue to proliferate so that there is an accumulation of primitive cells referred to as blast cells
