Cancer Bio

Question 1

Gene amplifications can take the form of double-minutes or homogeneously staining regions (HSRs), both of which can be detected by FISH. What is the difference between these two?

Answer 1

Double-minutes - extrachromosomal material

HSRs - intrachromasomal amplification

Question 2

What is Li-Fraumeni syndrome?

Answer 2

germline missense mutation of p53

Question 3

What familial cancer syndrome is caused by mutation in the APC tumor suppressor gene?

Answer 3

Familial adenomatous polyposis

Question 4

Mutation in which tumor suppressor gene causes familial gastric cancer?

Answer 4

E-cad

Question 5

Ras proteins (ie H-ras, K-ras, N-ras) are the most frequently mutated oncogene family in human cancers. What are they?

Answer 5

GTP-binding signal transducers

Question 6

What is the most important regulator of G1–>S transition?

Answer 6

Rb - blocks progression into S by sequestering E2F

Question 7

Binding of Fas to FasL induces recruitment of the initiator procaspase __.

Answer 7

Procaspase 8

Question 8

What are the effector caspases?

Answer 8

3,6,7

Question 9

Mitochondrial-dependent cell death is achieved through activation of initiator caspase __.

Answer 9

Caspase 9 - intrinsic pathway

Question 10

Release of cytochrome c from the mitochondria is regulated by the _____ protein family.

Answer 10

Bcl-2

Question 11

What impact does telomere shortening have in normal cells? In p53 deficient cells?

Answer 11

normal –> senescence

p53 deficient –> genomic instability –>accelerated tumorigenesis

Question 12

What is the most important growth factor for stimulation of neoangiogenesis?

Answer 12

VEGF2

Question 13

What is the function of VHL protein?

Answer 13

Targets HIF for ubiquitin-mediated degradation

Question 14

What is the function of thrombospondin (TSP-1)?

Answer 14

antiangiogenic

Question 15

What happens to expression of E-CAD and NCAM as cells become more invasive?

Answer 15

Loss/decreased expression

Question 16

Mutation in MSH and PMS genes can cause hereditary nonpolyposis colon cancer. What cellular pathway do these genes participate in?

Answer 16

Mismatch repair

Question 17

What is microsatellite instability?

Answer 17

Mutation in the endogenous repeat sequences throughout the genome

Question 18

Ataxia telangiectasia leads to increased radiosensitivity. What is a hallmark of AT cells following ionizing radiation?

Answer 18

Failure to arrest in S phase

“radioresistant DNA synthesis”

Question 19

What is recQ and when in the cell cycle is it most highly expressed?

Answer 19

Family of DNA helicase proteins, expressed in S phase

Function to monitor DNA replication fork for damage

Question 20

Mutation of recQ helicases lead to what 3 syndromes?

Answer 20

Bloom syndrome (BLM)
Werner syndrome
Rothmund-Thompson syndrome

Question 21

How are cytokine signals propagated intracellularly?

Answer 21

JAK signaling pathways