Ch. 4: Oncogenes Flashcards
DNA from ________ is
capable of inducing cancer
chemically induced cancer cells
proto-oncogene
Normal cellular gene that, upon alteration can
acquire the ability to function as an oncogene (induce cancer)
What do proto-oncogenes do?
In general-
* promotes cell division/proliferation
* are highly regulated in the normal cell
oncogene
A cancer-inducing gene,
a gene that can transform cells
Where do oncogenes come from?
In general a result of aberrant activation of a
proto-oncogene
How do proto-oncogenes become oncogenes?
- gene amplification
- expression
- structure/function
What is a gene amplification?
increased copies of a gene in the genome of a cell
How many copies of a gene are usually present in a normal human?
2
How many copies of the MYC gene are present in gastric cancer cells?
2-10+
What is FISH? What is it used for?
- FISH (fluorescent in situ hybridization)
- it is used to visualize/differentiate the MYC genes in the gastric cancer cells (or more general)
Amplification of ERBB2 leads to…
decreased survival
Kaplan-Meier Survival Plot
Status of patients (disease-free survival, overall survival) is plotted as a function of the time elapsed following initial diagnosis or treatment.
Disease-free survival:
Time after treatment in which no sign of cancer is found.
Measure of cancer not coming back.
Significance/Interpretation:
Amplification of ERBB2 is implicated in malignancy (spread of cancer)
can entire regions of chromosomes be amplified?
yes
how to read a heatmap (slide 10)
- Each column corresponds to 1 tumor/patient (x- axis)
(360 samples in total) - Each row is a gene in part of chromosome 17
(the part that contains ERBB2) (y-axis) - Green- if that particular gene has a relative decrease in RNA
expression - Red- if that particular gene has a relative increase in RNA
expression
What is gene expression (gene regulation)?
- DNA -> RNA -> Protein
- Can refer to how much RNA or protein is being made from a
particular gene
high expression
lots of RNA/protein being made from that gene
Low expression
lower levels of RNA/Protein being made from that gene
What does chromosomal translocations do to protein expression?
change protein expression
What can chromosomal translocation do to a gene?
can remove a gene from its non-coding regulatory regions
What can point mutations do to proteins?
change their structure/function
What is a point mutation?
changing/deleting/adding one base pair of a genome
What is RAS?
a potent point-mutated oncogene that is mutated in many cancers
What do chromosomal translocations do to proteins?
change their structure/function
