Genetics at work in cancer Flashcards
What are the genes that are involved in cancer?
Oncogenes - switch these on for cell division
Tumour supressors - switch these on to stop cell division
DNA repair genes - repair DNA damage
Drug Metabolism - genes that metabolise carcinogens
Describe Retinoblastoma? Dominant? Recessive? etc
It is autosomal dominant
It is a classical tumour suppressor gene
It has variable penetrance
You need 2 copies of the gene to get the tumour
Both of the copies may be lost due to somatic mutation
What are 3 mechanisms of gene activation?
Duplication of the gene
Activation of the gene promoter
Change in amino acid sequence – active protein configuration
What is FISH used for?
Specific detection of DNA sequences on chromosomes
What does senescence mean?
The cell is not functioning and not dividing anymore
Name some mechanisms of DNA repair?
Cell cycle checkpoints Direct repair Base excision Nucleotide excision Mis-match repair complex
Describe the mis-match repair complex?
It detects a mis match such as A C and excises it by the mis-match repair complex
What does a mutation in BRCA1 indicate?
Familial breast cancer
Involved in DNA strand repair
Should you test the person who if affected first or the person that is believed to have a potential mutation?
The person who is affected! Symptomatic test
What is a polymorphism?
Any variation in the human genome that does not cause a disease in its own right. It may however, predispose to a common disease
What are SNPs?
Alterations in DNA sequence
Every 100 to 300 bp
Up to 10 million in total
About 3 million variants in any one person
Each given a unique id (rs number)
What treatments could you have if you have cancer?
Screening Breast examination
Mammography
Hormonal Manipulation Tamoxifen
Surgical Intervention Mastectomy
Oophorectomy
Describe p53?
Important tumour suppressor cell
Activate DNA repair proteins
Arrest cell growth at the G1/S cell cycle checkpoint
Initiate apoptosis if DA damage irreparable
