Genetics: Genetics and Cancer Flashcards
what type of mutations is cancer largely caused by
post-zygotic - somatic mosaicism
describe the heterogeneity of cancer
the same disease can be caused by many different types of mutations
driver mutations
mutations that drive carcinogenesis
passenger mutations
mutations that are accumulated as a result of cancers instability
somatic mutations (in terms of cancer)
not inherited, mutations caused by carcinogenesis
epigenetics
the study of mutations in the gene sequence but not in the DNA sequence
what is methylation
prevents transcription by binding with histones
where does hypomethylation occur
many tumour types
where does hypermethylation occur
tumour suppressor genes
what are oncogenes activated by
proto-oncogenes that are activated by point mutations, translocations or gene amplification leading to oncogenes gaining dominant control of function mutations
as a result of mutations what might tumour cells possess
- own EC growth factors
- over expression of growth factor receptors
- continually active proteins that don’t require phosphorylation
vemurafenib MoA
inhibits continually active proteins therefore stopping proliferation
herceptin MoA
binds to receptors blocking proliferation signalling
what is the Philidelphia Chromosome
translocation between 9 and 22 that can cause leukaemia
what types of signal do normal cells rely on to regulate growth but cancer cells become unresponsive to
anti-growth signals
are tumour suppressor mutations recessive or dominant
recessive
how does hereditary Rb present
in babies with FHx
how does sporatic Rb present
in older children with no FHx
describe the 2 hit hypothesis
the first mutation increases cancer suscpetibility, the second leads to cancer
tumour suppressor genes (6)
Rb BRCA 1 BRCA 2 p53 PTEN APC
what is the normal function of tumour suppressors
supress cell division
what is the normal function of oncogenes
activates cell division
are oncogene mutations recessive or dominant
dominant
what types of mutations are tumour suppressor mutations normal caused by
point - deletions
