Genetic predisposition to cancer Flashcards
What are oncogenes
Mutated protoncogenes
What do oncogenes cause
Accelerated cell division
What is the result of tumour to tumour suppression genes
1st mutation- susceptable carrier accelerated cell division
2nd mutation- leads to cancer
What are the Cancer associated with BRCA-1
Breast cancer -50-85%
Second primary breast cancer - 40-60%
Ovarian cancer 15%-45%
Name the 2 types of gene mutations in which cancer arises from?
Somatic and Germline mutations
Name the 3 types of genes associated with Cancer?
Oncogenes
Tumour suppressor genes
DNA damage-response genes
Location for somatic and germline mutation
Somatic occurs in nongermline tissue and are nonheritable
Germlinic mutations are present in egg or sperm and are heritable
Explain the difference between Benign, malignant, Dysplastic
Benign - lack ability to metastasize, rarely or never become cancerous but can still cause health effects due to pressure on other organs
Dysplastic - ‘benign’ but could progress to malignancy, cells show abnormalities of appearance and cell maturation
Malignant - Able to metastasize
How does HNPCC (Hereditary non-polyposis coloerectal cancer) occur?
Failure of Mismatch repair genes
Nature of oncogene in cancers
It is the dominant gene in effect
Nature of the TSG (Tumour Suppressor Gene)
Recessive genes in effect
Risk factors of breast cancer (5)
Ageing
Family history
Dietary factors
Lack of exercise
Late menopause
Role of mismatch repair (MMR) and where
Corrects errors that occur during DNA replication like single base mismatches or short insertions and deletions
TSG normal effect, 1st mutation and 2nd mutation
Normal genes prevent cancer
1st mutation gene acts as a susceptible carrier
2nd mutation leads to cancer
What can mutation in proto-oncogene result in
Gene transforming into an oncogene which accelerates cell division
