4.15 MolecularBio of Cancer

Question 1

Tumor suppressor genes known as

Answer 1

caretaker gene, gatekeeper gene, landscaper gene.

Question 2

Are cancers genetic?

Answer 2

Some are. Some are sporadic.

Question 3

Viral induced cancer example?

Answer 3

HPV

Question 4

Root cause of all Neoplasms?

Answer 4

Damaged DNA

Question 5

What is p53

Answer 5

Potent tumor suppressor implicated in many tumors.

Question 6

What induces tumors?

Answer 6

Carcinogens

Question 7

If there are multiple locus contributing to a phenotype this is known as

Answer 7

Locus heterogeneity

Question 8

What is the role of proto-oncogenes used for normal cell development?

Answer 8

Regulation of cell cycle
Regulation of differentiation
Regulation of senescence

Question 9

What is transformation?

Answer 9

The process by which a cell loses its ability to remain constrained in its growth properties

Question 10

What do tumor suppressor genes do?

Answer 10

They either dampen or repress up-regulation of the cell cycle or promote apoptosis.

• Repress the continuation of the cell cycle
• Link entrance of cell cycle to undamaged DNA
• Link apoptosis to damaged DNA
• Adhesion/contact inhibition upkeep
• DNA Repair proteins

Question 11

Why is getting frequent sunburns related to cancer?

Answer 11

When you burn, your cells will apoptosis and creates fresh new layer of cells. When there are repeated burns and constant apoptosis it can lead to mutation and cancer

Question 12

How can you get retinoblastoma?

Answer 12

Inherited- gets one bad copy, then gets a mutation in the other good allele
Sporadic- has two unlucky mutations in both copies
Difference is whether you inherit a bad copy, or get 2 good ones

Question 13

What gene mutations occurs in Retinoblastoma?

Answer 13

Chromosome 13, RB1 gene

Question 14

What class of cancer causing gene does retinoblastoma fall? Oncogene or tumor supporessor gene?

Answer 14

Tumor suppressor because it is knocking out something

Question 15

Explain the two hit hypothesis?

Answer 15

Both alleles for a tumor suppressor must be mutated out as one is haplosufficient for tumor suppression

Question 16

What suppressor genes do not follow the two- hit rule and why?

Answer 16

P53 does not it is a potent tumor suppressor

Question 17

I have a proto-oncogene that is regulating the cell cycle. A mutation in that gene creates a growth hormone receptor that is constitutively “on.” This mutation is a

Answer 17

Gain of function mutation

Question 18

I have a tumor suppressor gene that needs a “two-hit” to take out. The mutation that I am creating if I need to hit both alleles to affect the phenotype is a

Answer 18

Loss of function mutation

Question 19

If a oncogene can create an oncogenic state by mutating one copy of a proto-oncogene, the oncogene is probably going to be a ____ mutation to the proto-oncogene.

Answer 19

Dominant

Question 20

A tumor suppressor that needs a “two-hit” would classify the mutated allele as being a ____ mutation.

Answer 20

Recessive

Question 21

Describe the philadelphia Chromosome

Answer 21

Translocation mutation. BCR and ABL next to each other prevents cells from accidently being activated. This results in leukemia.

Question 22

What is Senescence?

Answer 22

irreversible state of dormancy

Not always a bad thing, some cells are naturally dormant

Question 23

Apoptosis

Answer 23

programmed cell death
Not always a bad thing as development requires regulated apoptosis
Can be induced by the immune system

Question 24

How can DNA repair lead to tumors?

Answer 24

Rate of DNA damage in cells varies between 10,000 to 1,000,000 molecular lesions per cell per day
- Increase chances of mutation

Question 25

What happens when you have excess Oxygen to the DNA?

Answer 25

ENDOGENOUS DNA DAMAGE: Oxidation of DNA- Reactive oxygen species that creates DNA damage. ROS is created by WBC

Question 26

Exogenous DNA Damage

Answer 26

Free radicals and ROS can be created by many sources outside of the body Intercalating agents, viruses and plant toxins - Aflotoxin- Aspergillus parasiticus and A. flavus

Question 27

How is DNA repaired when there is a single strand break?

Answer 27

uses complementary strand

Question 28

How is DNA repaired when there is a double strand

Answer 28

Non-homologous end joining (DNA Ligase IV) Microhomology-mediated end joining Homologous recombination (like chiasma formation)

Question 29

What does DNA use for repair during the G2 phase if needed?

Answer 29

Sister chromatid or homologous chromosome

Question 30

How is a malignant tumor created?

Answer 30

DNA injury (Dysplasia)--> Continued DNA injury (Carcinoma in situ)--> Further DNA injury (Early invasive carcinoma through basement membrane)--> Invasion of blood vessels lymphatics with metastasis

Question 31

Cancer grading

Answer 31

Grade I Well differentiated Grade II- Moderately differentiated Grade III- Poorly differentiated

Question 32

What kills you when you have cancer?Why are tumor cells hot?

Answer 32

Cancer cells use up your nutrients. They are hot because they are burning up your sugar and goods.

Question 33

What is the best cancer therapy?

Answer 33

Assasinate: Immune system boosters. Your cells, immune system fights the cancer

Question 34

What are other forms of cancer treatment

Answer 34

Cut- surgery Poison- Chemotherapeutics Burn- radiotherapeutics

Question 35

How can we get cancer?

Answer 35

Activation of oncogenes | Destruction of tumor suppressor genes

Question 36

Describe the cell cycle

Answer 36

b. G1 Growth phase. Most cells in this phase c. Cycle Check- “Stop signs” d. S- Duplicate DNA—Form of aneuoploidy. Cell is turned off and no longer reactive. Only concerned of dividing. e. G2- DNA finished replicating. Rest of cell gets on board. f. Cycle Check- Checks to see if all cell components are there (Mitochondria, golgi, etc). g. M- Mitosis metaphase h. G0- They step out of the cell phase. Will not go through mitosis again. Can’t easily induce them.

Question 37

How do oncogenes effect the cell cycle

Answer 37

they kill the "stop signs", cycle checks. This activates the system

Question 38

What part of the cell cycle do protooncogenes turn on?

Answer 38

G1 phase-- same gene involved in gene development

Question 39

How is the cell cycle regulated?

Answer 39

CDK