T1Q6 Cancer Inheritance Flashcards
cytogenetic observation
ex. retinoblastoma
positional cloning
?
Cloning
?
GWAS
?
Knudson
failure of tumor suppressors is inherited recessively, but is expressed dominantly
reason: 1st= suspectible, 2nd hit= cancer!
penetrance
the likelihood an organism with a certain genotype exhibits the corresponding phenotype
linkage analysis
axiom: recombination occurs less frequently amongst physically close genes than genes on different chromosomes or those located far apart on the same chormosome
BRCA1
penetrance of breast cancer increases with age in ALL women
women with a mutation have significantly higher risk of developing breast cancer at an earlier ager
a negative result
?
HNPCC
hereditary non-polyposis cancer
inherited colon cancer without polyps
PCR-based allelotyping
a panel of microsatellite repeats are used to discriminate between cancer-prone and non-cancer prone regions
“this analysis was termed an allelotype, in analogy with a karyotype”
microsatellite instability
A change that occurs in the DNA of certain cells (such as tumor cells) in which the number of repeats of microsatellites (short, repeated sequences of DNA) is different than the number of repeats that was in the DNA when it was inherited. The cause of microsatellite instability may be a defect in the ability to repair mistakes made when DNA is copied in the cell. Also called MSI.
what makes a growth-regulatory gene a potential target for inactviation by microsatellite instability?
a microsatellite within its coding exon, or in important promoter/ intronic locations
Ex. TGF-Beta Type II Receptor
Features Suggestive o Inherited Predisposition to Cancer (4)
- early age of onset
- multiple cancers fitting a recognized syndrome
a. multiple cancers in the same person
b. multiple cancers in the family - autosomal dominant pattern of inheritance
variable number tandem repeat
is a location in a genome where a short nucleotide sequence is organized as a tandem repeat.
