What do a small proportions of cancers happen due to?
Increased inherited predisposition to cancer (genetic)
What are the 2 different kinds of gene mutations that cancer can arise from?
Where to somatic mutations occur?
In somatic tissue, nongermline
What can you say about the inheritability of somatic and germline mutations?
Somatic cannot be inherited and germline can
Where are germline mutations present?
In egg or sperm
What are some genetic processes associated with cancer?
Tumour suppresor genes
DNA damage response genes
What are proto-oncogenes?
Normal gene that codes for proteins to regulate cell growth and differentiation
What can mutations change into oncogenes and what does this do?
Proto-oncogenes which accerlerates cell division
What are tumour suppresor genes?
Genes that inhibit cell cycle or promotes apoptosis
What happens when tumour suppresor genes fail?
What are DNA damage response genes?
Repair mechanism for DNA
What happens when DNA damage response genes fail?
Cancer arises due to speeding the accumulation of mutations in other critical genes
What is an example of a DNA damage response gene?
Mismatch repair genes (MMR genes)
What do mismatch repair (MMR) genes do?
Corrects errors that spontaneously occur during DNA replication like single base mismatches or short insertions and deletions
What does mismatch repair failure lead to?
Microsatellite instability (MSI) where there is the addition of nucleotide repeats, which is the phenotypic evidence that MMR is not functioning normally
What is microsatellite instability (MSI)?
Where there is an addition of nucleotide repeats, which is phenotypic evidents that mismatch repair genes (MMR) are not working correctly
What are the 3 kinds of tumours?
What are some properties of benign tumours?
Lack the ability to metastasize
Rarely or never become cancerous
Can cause negative health benefits due to pressure on other organs
What are some properties of dysplastic tumours?
Benign but could progress to malignancy
Cells show abnormalities of appearance and cell maturation
What is a unique property of malignant tumours?
Able to metastasize
What are some other causes of cancer in relation to genes?
Autosomal recessive syndromes
Multiple modifier genes of lower genetic risk
What are de novo mutations?
Occur in germ cells of parents with no family history of hereditary cancer syndrome
What are de novo mutations common in?
Famial adenomatous polyposis
Multiple endocrine neoplasia 2B
What is hereditory retinoblastoma?
Most common eye tumour in children
What is the type of inheritence of most cancer susceptability genes?
What are some risk factors for breast cancer?
Nulliparty (condition where woman cannot give birth)
Dietary factors (alcohol)
Lack of exercise
What is nulliparty?
Condition where woman cannot give birth
What are some genes that increase hereditory susceptability to breast cancer?