Tumour Pathology 5 Flashcards

1
Q

What do tumour-supressor genes normally do?

A
  • Negatively regulate mitosis (Rb gene)
  • Regulate Apoptosis (p53)
  • Regulate DNA repair (p53)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do proto-oncogenes do?

A

Code for proteins that regulate normal growth.
(growth factors & receptors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does the Rb gene -ve regulate mitosis?

A

Rb gene codes for pRb
E2F promotes DNA synthesis
-> pRb deactivates E2F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What other mutations can mimic pRb loss?

A
  • Mutational activation of Cyclin D or CDK4 (their complex phosphorylates & deactivates pRb)
  • Mutational inactivation of CDK inhibitors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does Cyclin D/CDK4 complex normally do?

A

Phosphorylates pRb causin it to deactivate.
Allows E2F to promote cell division
[Occurs when external stimuli signal for mitosis to occur]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Another name for Tumour-Supressor genes?

A

Anti-Oncogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

whats the two-hit hypothesis:?

A

Two mutations are required to inactivate tumour-suppresor genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the two forms of oncogenesis? (mutation to anti-oncogenes)

A

Sporadic
Inherited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain inherited oncogenesis:

A
  • One allele of Rb gene is inherited defective
  • Other copy undergoes somatic point mutation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain sporadic oncogenesis?

A

Both ‘hits’ or mutations occur in a single cell (i.e. not inherited)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Whats the difference between an inherited cancer syndrome and a familial cancer?

A

Inherited Cancer syndrome:
- Strong family histroy of unusual cancers
- Autosomal Dominant inheritance of a single mutant gene
Familial Cancer:
- Family cluster of cancers
- Multifactorial inheritance
- Individual predisposition is unclear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Examples of inherited cancer syndromes?

A

Familial Retinoblastoma
FAP
Multiple Endocrine Neoplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Examples of Familial Cancers:

A

Some breast or ovarian cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How can an proto-oncogene become an oncogene?

A

Altered structure by mutation
Dysregulation of expresssion by gene amplification/overexpression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do oncogenes code for?

A

Oncoproteins
e.g. growth factors, nuclear regulatory proteins, cell cycle regulators etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the mechanisms of viral carcinogneneiss?

A
  • Retrovirus inserts oncogene into host DNA
  • Viral promoter causes pro-oncogene over expression
17
Q

Examples of DNA viruses known to cause cancer?

A

HEP B - Liver Cancer
Herpes (epstein-barr specifcally) - Burkitt Lymphoma
HPV - Cervical Cancer

18
Q

Mechanism of chemical carcinogenesis:

A

-> Chemical reacts iwth DNA to form DNA adducts
-> DNA adducts at particular chromosome sites leads to :
-> Oncogene activation or tumour-supressor gene deactivation

19
Q

What kind of mutations occur in most cancers?

A
  • Activation or several oncogenes
  • & loss of 2 or more anti-oncogenes
20
Q

Stages of carcinogenesis:

A
  • Normal Cell
  • DNA damage
  • GEnomic mutation
  • Oncogene activation/anti-oncogene supression
  • Dysregulation
  • Tumour progression
  • Malignant Neoplasm