Ch. 4: Oncogenes

Question 1

DNA from ________ is
capable of inducing cancer

Answer 1

chemically induced cancer cells

Question 2

proto-oncogene

Answer 2

Normal cellular gene that, upon alteration can
acquire the ability to function as an oncogene (induce cancer)

Question 3

What do proto-oncogenes do?

Answer 3

In general-
* promotes cell division/proliferation
* are highly regulated in the normal cell

Question 4

oncogene

Answer 4

A cancer-inducing gene,
a gene that can transform cells

Question 5

Where do oncogenes come from?

Answer 5

In general a result of aberrant activation of a
proto-oncogene

Question 6

How do proto-oncogenes become oncogenes?

Answer 6

• gene amplification
• expression
• structure/function

Question 7

What is a gene amplification?

Answer 7

increased copies of a gene in the genome of a cell

Question 8

How many copies of a gene are usually present in a normal human?

Answer 8

2

Question 9

How many copies of the MYC gene are present in gastric cancer cells?

Answer 9

2-10+

Question 10

What is FISH? What is it used for?

Answer 10

• FISH (fluorescent in situ hybridization)
• it is used to visualize/differentiate the MYC genes in the gastric cancer cells (or more general)

Question 11

Amplification of ERBB2 leads to…

Answer 11

decreased survival

Question 12

Kaplan-Meier Survival Plot

Answer 12

Status of patients (disease-free survival, overall survival) is plotted as a function of the time elapsed following initial diagnosis or treatment.

Question 13

Disease-free survival:

Answer 13

Time after treatment in which no sign of cancer is found.
Measure of cancer not coming back.

Question 14

Significance/Interpretation:

Answer 14

Amplification of ERBB2 is implicated in malignancy (spread of cancer)

Question 15

can entire regions of chromosomes be amplified?

Answer 15

yes

Question 16

how to read a heatmap (slide 10)

Answer 16

• 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

Question 17

What is gene expression (gene regulation)?

Answer 17

• DNA -> RNA -> Protein
• Can refer to how much RNA or protein is being made from a
  particular gene

Question 18

high expression

Answer 18

lots of RNA/protein being made from that gene

Question 19

Low expression

Answer 19

lower levels of RNA/Protein being made from that gene

Question 20

What does chromosomal translocations do to protein expression?

Answer 20

change protein expression

Question 21

What can chromosomal translocation do to a gene?

Answer 21

can remove a gene from its non-coding regulatory regions

Question 22

What can point mutations do to proteins?

Answer 22

change their structure/function

Question 23

What is a point mutation?

Answer 23

changing/deleting/adding one base pair of a genome

Question 24

What is RAS?

Answer 24

a potent point-mutated oncogene that is mutated in many cancers

Question 25

What do chromosomal translocations do to proteins?

Answer 25

change their structure/function