Genetics - Cancer Genetics Flashcards
When do we get a compromising of a cell function?
When a functional or regulating region of DNA is damaged/mutated
What are cancer genes?
Critical gene DNA sequence that will compromise cell function
What types of cancer genes do we have?
Tumour suppressor genes which are silenced
Proto oncogenes which are over expressed
What factors can lead to cancer?
Environment
Exogenous factors
Hereditary
What are benign tumours?
Well differentiated
Slow growth
Capsulated
Non invasive
What are malignant tumours?
Poorly differentiated
Fast growth
Invade local tissue
Integrated
What are the 6 hallmarks of cancer needed for successful cancer?
Self sufficiency in growth signals Insensitivity to anti growth signals Evading apoptosis Limitless replicative potential Sustained angiogenesis Tissue invasion/metastasis
What 2 hallmarks have recently been added to the classic 6
Genome instability
Evading immune destruction.
Give an example of evading immune destruction
PD1 protein found on normal cells and tumour cells
What does the lifetime risk of developing cancer correlate with?
How often stem cells in that tissue divide
What are germline cells?
Cells which produce our gametes - undergo meiosis and mitosis.
What do germline mutations lead to?
Heritable cancer
What are somatic cell mutations?
Mutations occurring in any non-germline cell
Are somatic cell mutations heritable?
no
How do we get cancer families?
Cancer predisposing mutation may occur in germline so is inherited
What increases the risk of breast cancer by 80%?
Abnormal BRCA-1/BRCA-2 gene
What increases the risk of ovarian cancer by 55%?
Abnormal BRCA-1 gene
How do germline mutations compare to somatic?
Smaller and indistinguishable
What is a silent mutation?
Mutations has no effect as same amino acid is produced
What is a mis sense mutation?
Codons code for a completely different amino acid
What is a non sense mutation?
Mutation leads to premature stop codon
How do somatic cell mutations compare in size?
Can be much larger
What is chromosome instability?
Higher rate of chromosome mis segregation can lead to alterations in chromosome number
How do we get chromosome instability?
Defective cell cycle control