41. DNA Damage, Oncogenes and Tumour Suppressor Genes Flashcards
What characterises a benign neoplasm?
Localised growth
Grow by expansion
Basement membrane not breached
What characterises a malignant neoplasm?
Capable of invasion and metastasis
Grow by infiltration
Breach basement membrane
What is the name for cancers that arise from epithelial cells?
Carcinomas
What is the name for cancers that arise from the mesoderm?
Sarcomas
What is the name for cancers of the blood and lymph systems?
Lymphoma
Leukaemia
What is the clonal evolution model?
Mutant tumour cells with a growth advantage are selected and expanded
What is the cancer stem cell model?
Some tumour cells can self-renew and generate diverse tumour cells
What are proto-oncogenes?
Normal activity promotes cell proliferation
Oncogenes=excessively active
What are tumour suppressor genes?
Inhibit cell proliferation or promote apoptosis
What are care taker genes?
Ensure accurate replication, repair and segregation of DNA
Mutation leads to genomic instability
What are the 6 hallmarks of cancer?
Growth signal autonomy Evasion of growth inhibitory signals Evasion of apoptosis Unlimited replicative potential Angiogenesis Invasion and metastasis
How can tumour suppressor genes be inactivated?
- deletion
- point mutation
- methylation of promoter (TF can’t bind)
- miRNAs cause post-transcriptional silencing
What is retinoblastoma caused by?
Mutation or deletion of RB gene (tumour suppressor)
How can proto-oncogenes be activated?
Point mutation
deletion
gene amplification
chromosome rearrangement
What oncogene is often affected in neuroblastoma?
MYCN
