Overview of Cancer and Genetics Flashcards
Malignant?
spread into or invade nearby tissue
Tissue changes that are not cancer (3)
- Hyperplasia
- Dysplasia
- Carcinoma in situ
Features of Hyperplasia (2)
- cells divide faster than normal
- cells and tissue organisation look normal
Features of Dysplasia (2)
- cells look abnormal
- changes in tissue organistion
Why is Carcinoma in situ not cancer? (2)
- cells do not spread beyond original tissue
- cells do not invade nearby tissue
What do recessive mutations do? (2)
- inactivate the affected gene
- lead to a loss of function
Dominant mutations lead to…
gain of function
Somatic mutations
genetic changes that occur after conception
What causes somatic mutations?
damage to DNA from environmental exposures
Germline mutations
mutations in DNA inherited from parents
Germline mutations found in…
every cell of offspring
Drivers of cancer (3)
- Proto-oncogenes
- Tumour Suppressor Genes
- DNA repair genes
Oncogenes
Mutated version of proto-oncogenes
What type of mutation occurs on proto-oncogenes?
Typically dominant
Function of proto-oncogene (3)
- stimulate cell division
- inhibit cell differentiation
- halt cell death
Function of oncogene (3)
- increase cell division
- decrease cell differentiation
- inhibit cell death
Gain of function mutations converting proto-oncogenes into oncogenes (3)
- point mutations
- gene amplification
- chromosome rearrangement
Result of point mutation on proto-oncogene (2)
- hyperactive protein
- normal amounts produced
Result of gene amplification on proto-oncogene (2)
- normal protein
- greatly overproduced
Function of tumour suppressor gene
encode proteins that, when activated, inhibit cell proliferation
What type of mutation occurs on tumour suppressor genes?
Recessive
How does Hereditary Cancer occur? (3)
- all cells lack 1 of the 2 normal copies of tumour suppressor gene
- due to germline mutation
- tumours then occur where the remaining copy is lost or inactivated by a somatic mutation
How does Non-Hereditary Cancer occur? (2)
- all cells have 2 functional copies of the tumour suppressor gene
- so 2 somatic mutations need to occur to lose or inactivate TS genes for tumour to occur
