Cancer I

Question 1

Oncogenes

Answer 1

Involves single mutation event and activation of gene causing proliferation; gas pedel
dominant
Gain of function with mutation

Question 2

Tumor suppressor genes

Answer 2

involve genes that inhibit growth; breaks
recessive
Loss of function with mutation

Question 3

What can hijack proto-oncogenes and activate them by either over-expression or cause mutations of proto-oncogene?

Answer 3

Retroviruses

Question 4

What was the first human oncogene discovered and is a monomeric GTPase for signal transduction?

Answer 4

Ras

Cannot shut off by hydrolyzing GTP to GDP

Question 5

What do proto-oncogenes become when activate?

Answer 5

oncogenes that drive cell proliferation

Question 6

Oncogene mutation are dominant or recessive?

Answer 6

Dominant. only one allele needs to be present for activity

Question 7

What are the mechanisms of oncogene activation?

Answer 7

1. Deletion of point mutation in coding sequence - hyperactive protein
2. Regulatory mutation - normal protein overproduced
3. Gene amplification - normal protein overproduced
4. Chromosomal rearrangement - both

Question 8

What are proteins that inhibit apoptosis?

Answer 8

Bcl2

Question 9

Describe other situations causing cancer

Answer 9

Ligands: if ligands produced constitutively they cause proliferation and growth all the time (cancer cells produce own ligand - autocrine signaling)
Receptors: TKR, when constitutively produced they dont need a ligand
Transcription factors: overproduction can lead to oncogene
Cell cycle proteins: any thing that can cause cell proliferation-overproduction leads to cancer

Question 10

What are transformed cells?

Answer 10

Small colonies of proliferating cells caused by oncogene

Question 11

Bcl2 oncogene is an example of what?

Answer 11

rearrangement mutation