2J- Cancer Genetics

Question 1

What do tumor supressor genes normally block?

Answer 1

uncontrolled cell proliferation by participating in the cell cycle regulation pathways.

Question 2

What happens when the pRb molecule is phosphorylated?

Answer 2

It is inactive and allows the cell to proceed into the S phase.

Question 3

What molecules encodes pRb?

Answer 3

RB1

Question 4

What would happen if there is a loss-of-fxn mutation, deletion or hypermethylation in RB1?

Answer 4

pRb is not made there is uncontrolled cell division

Question 5

What would happen if there are mutations in the CDK inhbitors?

Answer 5

uncontrolled cell growth

Question 6

What are oncogenes?

Answer 6

They are genes that cause excessive cell proliferation

Question 7

What genes typically make oncogenes?

Answer 7

proto-oncogenes (i.e. genes involved in regulation of normal cell growth)

Question 8

What are some examples of proto-oncogenes?

Answer 8

GFs, GF receptors, signal transduction molecules and nuclear transcription factors

Question 9

Are tumor supressor genes caused by gain or loss-of-fxn?

Answer 9

Loss of fxn

Question 10

What types of mutations at the cell level causes problems in tumor supressor genes?

Answer 10

recessive

Question 11

Are oncogenes caused by gain or loss-of-fxn?

Answer 11

gain of fxn

Question 12

What types of mutations at the cell level causes problems in ocogenes?

Answer 12

Dominant

Question 13

Some boob cancers are the result of defective repair of what type of DNA damage?

Answer 13

double stranded breaks

Question 14

Some butt cancers are the result of defective repair of what type of DNA damage?

Answer 14

DNA mismatch repair

Question 15

Xeroderm pigmentosum is the result of defective repair of what type of DNA damage?

Answer 15

nucleotide excision repair

Question 16

What is the fxn of APC?

Answer 16

tumor suppressor gene, also participates in the phosphorylation and degradation of β-catenin

Question 17

What disease is caused by dysfxnl APC?

Answer 17

Familial adenomatous polyposis (FAP)

Question 18

What is the fxn of p53?

Answer 18

acts as a transcription factor that regulates genes that affect cell growth, prolif, and survival, induces apoptosis if DNA is damaged

Question 19

What makes p53?

Answer 19

TP53. If it is mutated, p53 isnt made.

Question 20

What disease is caused by dysfxnl p53?

Answer 20

Li-Fraumeni syndrome

Question 21

What is the fxn of BRCA1?

Answer 21

participates in the DNA repair process, especially in double stranded breaks.

Question 22

What disease is caused by dysfxnl BRCA1?

Answer 22

Familial breast and ovarian cancer

Question 23

What is the fxn of NF1?

Answer 23

It’s product, neurofibromin, plays a role in signal transduction by down-regulation of RAS

Question 24

What disease is caused by dysfxnl NF1?

Answer 24

Neurofibromatosis type 1

Question 25

A cell can initiate a tumor ONLY when it contains how many damaged alleles?

Answer 25

2

Question 26

What is the Multi hit concept of carcinogenesis?

Answer 26

more than one mutation is required for development of a tumor cell

Question 27

What is Familial Adenomatous Polyposis (FAP) ?

Answer 27

There are a large # of polyps, so there is a high probability that at least one will produce a cancerous tumor by age 45

Question 28

What causes Hereditary nonpolyposis colon cancer (HNCC)?

Answer 28

mutations occur in DNA mismatch repair genes

Question 29

What enzyme is present in 85-90% of tumors that replases temomeric segments?

Answer 29

telomerase

Question 30

What can gene mapping identify?

Answer 30

the region an inherited cancer gene is located but can’t identify the disease gene!

Question 31

What is Genomic Instability?

Answer 31

mutations, chromosome breaks, aneuploidy; contributes to tumorigenesis b/c mutations and chromosome defects can activate oncogenes or deactivate tumor suppressor genes