The cancerous cell

Question 1

What are the hallmarks of cancer?

Answer 1

Evading apoptosis

Self-sufficiency in growth signals

Insensitivity to anti-growth signals

Tissue invasion & metastasis

Limitless replicative potential

Sustained angiogenesis

Question 2

What are major cellular processes affected in cancer development?

Answer 2

1) Cell cycle
2) apoptosis is reduced
3) cell adhesion is impaired - tumour cells can detach
4) angiogenesis - deliver oxygen & nutrients to tumour

Question 3

What are the checkpoints of the mammalian cell cycle?

Answer 3

G1 - favourable environment?
G2 - DNA replicated? favourable environment?
Metaphase - chromosomes attached to spindle?

Question 4

What are types of mutations that occur in cancer?

Answer 4

point
amplification
deletions
chromosomal rearrangements

Question 5

What can expression of genes be influenced by?

Answer 5

• methylation of specific C in promoters

- Chromatin remodelling, post-trans mods in histones

Question 6

What are the 3 main genes involved in cancer?

Answer 6

Oncogenes

Tumour suppressor genes

Genes involved in DNA repair

Question 7

What is a dominant cancer mutation?

Answer 7

single mutation event in proto-oncogene

creates oncogene

enables oncogene to stimulate cell proliferation

Question 8

What is recessive cancer mutation?

Answer 8

mutation event - inactivates tumour suppression gene

2nd mutation even inactivates second gene copy on chromosome

suppressor gene eliminated

Question 9

What are the 3 ways a proto-oncogene is converted?

Answer 9

mutation in coding sequence

Gene amplification

Chromosome rearrangement

Question 10

What are functions of the proto-oncogenes?

Answer 10

Growth factors

Growth factor receptors

Signal transducers

Nuclear proto-oncogenes & transcription factors

Question 11

What is retinoblastoma?

Answer 11

eye cancer caused by a mutation in a tumour suppressor gene

can be hereditary as can inherit once mutant Rb gene already - only 1 more to mutate

Question 12

What happens when Rb (of retinoblastoma) is mutated?

Answer 12

doesn’t bind to transcription factor E2F

constant activation and progression of cells into S phase

Question 13

What are the virus oncogenes of HPV16?

Answer 13

E6 and E7 - highly growth promoting
E7 binds it and targets it for degradation
p53 - tumour repressor frequently mutated
E6 bind to p53 and degrade it

Question 14

What is a bacteria associated with gastric cancer?

Answer 14

Helicobacter pylori

elimination of H pylori by antibiotics reduces gastric cancer

chronic inflammation of gastric mucosa

Question 15

What can DNA replication errors be detected by?

Answer 15

MutS and MutL

Question 16

What are the stages of colon cancer

Answer 16

Small adenoma
Large adenoma
Carcinoma

Question 17

Inherited colon cancer account for what %?

Answer 17

10-15%

mutations in hereditary are similar to those in sporadic

Question 18

What is familial adenomatous polyposis?

Answer 18

0.01% colon cancer
single gene disorder
truncation mutations in APC protein

Question 19

What is HNPCC?

Answer 19

mutations in mis-macth repair enzymes hMLH1 and hMSH2

polyps fewer than FAP