Genetic Predispodition to Cancer Flashcards
does intragenic or extragenic DNA have strong cancer predisposition?
intragenic
what is a germline mutation?
a mutation in the sperm/egg causing family cancer syndromes
true or false
in germline mutations all cells are affected in the offspring
true
describe somatic mutations
these occur in non-germline tissues and are non-heritable
a child has a retinoblastoma and a germline mutation. what are they are risk of?
cancer in the other eye
a mutation in an oncogene can lead to what?
accelerated cell division leading to cancer growth
what are tumour suppressor genes?
normal genes that prevent cancer
what are oncogenes?
normal genes that regulate cell growth
describe DNA mismatch repair and how it could lead to cancer
so there is a base pair mismatch in the DNA which should normally be repaired but if it isn’t then a mutation in induced.
describe inheritability of autosomal dominant condition
> each child has a 50% chance of inheriting it
there are no skipped generations
equally transmitted by men and women
when should you suspect inheritance?
> 2 or more close relatives > multiple primary tumours > early age of diagnosis > bilateral/multiple rare cancers > evidence of autosomal dominant transmission > characteristic pattern of tumours
what intervention could be offered in a heritable cancer?
> counselling
increase awareness of symptoms and signs and lifestyle
screening
prophylactic surgery
what are the risks and limitations of genetic testing?
> there is a continued risk of sporadic cancer
does not detect all mutations
efficacy of interventions are variable
may result in psychological or economic harm
what are the benefits of genetic testing?
> identifies highest risk
identifies non-carriers
may relieve some anxiety
allows early detection and prevention strategies
what mutation is present in hereditary non-polyposis colon cancer?
mutation in the mismatch repair genes
