Cancer: The Basics

Question 1

What is a tumor?

Answer 1

Swelling (unregulated cell growth);

Question 2

What is malignancy defined as?

Answer 2

The ability to metastasize

Question 3

Can benign tumors kill patients?

Answer 3

Yes.

Question 4

Cancer cells are defined by what two heritable properties?

Answer 4

1) Reproduce in defiance of the normal restraints on cell division
2) Invade and colonize territories normally reserved for other cells

Question 5

Cancer cells usually arise from how many abnormal cells?

Answer 5

One

Question 6

How do cancer stages develop?

Answer 6

Clonal Expansion

Question 7

Explain clonal expansion.

Answer 7

Tumor progression involves successive rounds of mutation and selection, mutations gives individual cells a growth advantage over others.

Question 8

How does cancer develop?

Answer 8

In stages

Question 9

What is “immortalization”?

Answer 9

indefinite growth

Question 10

What is “transformation”?

Answer 10

Independence of growth factors

Question 11

What is “metastasis”?

Answer 11

Invasion and growth at a distant site

Question 12

What are the 5 properties involved with converting cells to cancer cells?

Answer 12

1) Loss of regulation of cell proliferation
2) Tendency to avoid apoptosis
3) Genetic instability
4) Ability to invade
5) Ability to metastasize

Question 13

What are the two types of genes critical to cancer development?

Answer 13

Oncogenes and TSG’s

Question 14

An oncogene is what type of mutation?

Answer 14

Gain of function

Question 15

Oncogenes act in what type of fashion?

Answer 15

Dominant; stimulate replication

Question 16

What type of mutation does a TSG undergo?

Answer 16

Loss of function, acts in a recessive manner (takes two hits)

Question 17

What was the first human oncogene discovered?

Answer 17

Ras (single point mutation)

Question 18

How do proto-oncogenes become oncogenic? (3 things)

Answer 18

1) Mutation in coding sequence
2) Gene amplification
3) Chromosome rearrangement

Question 19

What are gatekeepers?

Answer 19

They directly regulate cell growth, ex. Rb, p53, APC, p19 Arf, p16 Ink4

Question 20

What are caretakers?

Answer 20

They are involved in repairing DNA damage or maintaining genomic integrity (ATM, BRCA1, BRCA2)

Question 21

What is familial polyposis coli (familial adenomatous polyposis, FAP)

Answer 21

Hundreds of thousands of colon polyps by age 20, develop into colon cancer if not removed. It is an inherited, inactivated APC gene that causes it

Question 22

What is p53?

Answer 22

A tumor suppressor, “the guardian of the genome”

Question 23

At what cell cycle phase does p53 induce arrest?

Answer 23

G1 in response to DNA damage (p21 induction)

Question 24

Why does p53 arrest the cell cycle?

Answer 24

To repair DNA damage, if it is not fixable then cell it induced apoptosis

Question 25

Inactivation of p53 leads to?

Answer 25

Genome instability

Question 26

What protein of HPV binds and inactivated p53?

Answer 26

E6

Question 27

What is an inherited susceptibility to multiple cancers due to de defective p53?

Answer 27

Li-Fraumeni Syndrome

Question 28

What kind of cells have a possible role in the development of cnacer?

Answer 28

Stem Cells because they are relatively undifferentiated, have capacity for unlimited/self renewal, and ability to produce at least one highly differentiated cell type

Question 29

True or false, there are analogies between stem cells and cancer cells?

Answer 29

True; proliferative potential, give rise to normal tissues. Tumorigenic cancer cells undergo processes analogous to self-renewal and differentiation of normal stem cells.