Lectures 1/2

Question 1

What is cancer?

Answer 1

Cancer is a condition where abnormal cells grow and reproduce uncontrollably.

Question 2

What evidence is there for cancer being genetic?

Answer 2

-most carcinogens are also mutagens
-no mini epidemics so not contagious
-incidence increase with age in correlation with DNA damage
-chromosome instability a common feature
-defects in DNA repair increase probability of cancer

Question 3

What are the two types of mutation?

Answer 3

Somatic and Germ line

Question 4

What are germ-line mutations?

Answer 4

-mutations in every cell in the body
-passed directly from parent to child
-less common than somatic
-called inherited cancer

Question 5

What are somatic mutations?

Answer 5

-known as acquired mutations
-occur due to damages to genes during a persons lifetime
-aren’t passed from parent to child
-most common cause of cancer
-called sporadic cancer

Question 6

What are cancer genes?

Answer 6

Genes that before mutation have a normal function but once mutated can cause cancer

Question 7

What are the two main groups of cancer genes?

Answer 7

Oncogenes and Tumor suppressor genes

Question 8

What is the normal version of oncogenes?

Answer 8

Proto-oncogenes

Question 9

Are oncogenes dominant or recessive?

Answer 9

Tend to be dominant acting

Question 10

Can mutations in oncogenes be inherited?

Answer 10

Not usually

Question 11

Do Timor suppressor genes act recessively or dominantly?

Answer 11

Recessive acting

Question 12

Can tumor suppressor genes mutations be inherited?

Answer 12

Can be inherited in family cancer syndromes

Question 13

What are the usual function of Timor suppressor genes?

Answer 13

Usually prevent cell growth/division

Question 14

What happens when a tumor suppressor gene mutates?

Answer 14

You get a loss of function

Question 15

Example of an inherited tumor suppressor gene cancer?

Answer 15

Retinoblastoma

Question 16

What do Proto-oncogenes have as a usual function?

Answer 16

To promote cell growth and division

Question 17

What happens when a proto-oncogene becomes an oncogene?

Answer 17

Gain of function mutation

Question 18

What type of mutations occur in oncogenes?

Answer 18

Tend to have multiple mutations in a few codons affecting particular domains usually bias towards missense mutations

Question 19

What type of mutations occur in tumor suppressor genes?

Answer 19

Usually missense mutations and mutations that cause premature termination

Question 20

What are gatekeeper genes?

Answer 20

Act directly to restrain proliferation

Question 21

What are caretaker genes?

Answer 21

Act directly and maintain integrity of genome. Disruption leads to genomic instability DNA repair genes are a subgroup.

Question 22

What are landscaper genes?

Answer 22

Act indirectly to control the environment in which cells grow creating a microenvironment to aid cancer cells when mutated

Question 23

What are DNA repair genes?

Answer 23

A subclass of tumor suppressor genes indirectly involved in growth, inhibition or differentiation.

Question 24

What happens after inactivation of DNA repair genes?

Answer 24

-results in DNA damage going unrepaired
-leads to accumulation of mutations in the other cellular genes
-increasing the likelihood of damaging mutations in other genes

Question 25

What is retinoblastoma?

Answer 25

Common eye tumor is a tumor of the retinal stem cell.

Question 26

What are the signs of retinoblastoma?

Answer 26

Signs can be a white pupil

Question 27

What is the two-hit hypothesis?

Answer 27

Also known as the Knudson hypothesis, says that it takes both alleles to be inactived through mutations or epigenetic silencing.

Question 28

Why do inherited cancer occur earlier in life?

Answer 28

As they only need one mutation where as sporadic need two.

Question 29

What is loss of heterozygosity (LOH)?

Answer 29

A mutation where you lose one normal copy of a gene or a group of genes.