Ch. 23 Cancer Flashcards
metastasis
advanced tumors shed cells that travel to other parts of the body
Tumor growth
cells divide rapidly and constantly (crowd normal cells and rob nutrients)
Tumor suppressor genes
mutated recessive-acting inhibitory genes that cause cancer; cell division may be stimulated when inhibitory genes are made inactive
Oncogenes
mutated dominant-acting stimulatory genes that cause cancer- (have a stimulatory affect on the cell cycle)
Proto-oncogenes
oncogene prior to mutation; normal cellular gene responsible for basic ceullar function; when mutated they may become an oncogene
DNA repair genes
mutations in DNA-repair genes can increase the likelihood of acquiring mutations in these genes
If one or more required mutations are inherited…
less mutations would be required to produce cancer: Knudson’s Multistep Model
Most tumors arise from __________mutations
somatic mutations
The 1st mutation cell…
predisposed to proliferate faster
The 2nd mutation causes…
cells to divide rapidly
3rd mutation cell…
undergoes structural changes
The 4th mutation causes
cells to divide uncontrollably and invade outher tissue (malignant)
The rate of clonal evolution depends on…
the frequency with which new mutations arise
telomerase
activation of telomerase allows cells to divide indefinitely
Apoptosis genes
genes involved in signaling programmed cell death are often mutated
Vascularization genes
genes that stimulate angiogenesis are often overexpressed
cell adhesion genes
genes involved in intercellular interactions and attachment
miRNAs
microRNAs are often misregulated
kinase
an enzyme that adds a phosphate to a protein
Cyclin-dependent kinases
kinases that control key events of the cell cycle
CDKs are functional only when associated with a ______
cyclin (another protein)
Cyclin appears
at specific points in the cell cycle
The retinoblastoma protein helps control…
the progression through G1/S checkpoint
When RB binds to E2F does it activate or inactivate it
keeps it inactive
During G1…
concentrations of cyclin D and E increase and they combine with their CDK
After the cyclins binds to the CDK…
The CDK phosphorylate the RB, which inactivates it and it releases E2F which then stimulates transcription of genes
people _______ for a tumor-suppressor gene are predisposed to cancer
heterozygous
loss of heterozygosity for a tumor-suppressor gene often leads to
cancer
hormones (some) and growth factors bind to ____, and initiate a
cell surface receptors that transmit the message into the cell; signal transduction pathway
in the Ras signal transduction pathway, inactive Ras binds to
GDP
in the Ras signal transduction pathway, active Ras binds to
GTP
What happens in the Ras signal transduction pathway
bind of growth factor causes conformational change and phosphorylation, adaptor molecules bind to receptor and link to Ras, Ras binds GTP and is activated
What happens at the end of the Ras signal transduction pathway
activated MAP kinase moves to nucleus and activates TFs that stimulate transcription of cell cycle genes
Burkitt’s Lymphoma
a recurring reciprocal translocation between the q-arms of chromosomes 8 and 14
What genetic testing would you use to find Burkitt’s Lymphoma
fluorscence in situ hybridization
The Philadelphia Chromosome is an example of
a translocation that leads to a fusion protein
