cell cycle checkpoints in cancer

Question 1

How do cancer cells pass through G1 R checkpoint (2 points)

Answer 1

1. constitutively active growth factor signalling
2. R-point defects

Question 2

oncogenes cause cancer when …

Answer 2

they are over-expressed

Question 3

tumour suppressor genes cause cancer when …

Answer 3

their expression is lost

Question 4

Ret alterations

Answer 4

fusion translocation
or activation point mutation
- causes thyroid cancer

Question 5

Ras oncogene triggers signalling cascade which =

Answer 5

too much cyclin D,
= 95% of pancreatic cancer
= 50% of colon cancer
= 25% of all cancers

Question 6

TGF-beta …
(1) effect in epithelial cells
vs (2) effect in cancer

Answer 6

(1) blocks proliferation
(2) stimulates growth

Question 7

when TGF-beta binds TGF-beta Receptors I and II … it triggers

Answer 7

SMAD transcription factor cascade,
SMAD can bind SMD4,
= Cdki expression

Question 8

stress causes p53 to …

Answer 8

increase transcription a cdki

Question 9

MDM2 regulates

Answer 9

P53 activity in cells,
through directing Ub + degradation of P53