Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Parasitology > Transmissible Cancer > Flashcards

Transmissible Cancer Flashcards

1
Q

Mutations which cause cancer often occur in which genes?

A

Genes encoding:

  • Oncogenes
  • Tumour suppressor proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are examples of oncogenes?

A

Ras, Myc, RTK

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

Example of a tumour suppressor protein?

A

P53

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

What is the role of P5S?

A
  • Cell cycle checkpoint
  • DNA repair
  • Induction of apoptosis if DNA cannot be repaired
  • Increased cell adhesion to reduce tumour metastasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many copies of P53 are required to prevent formation of cancers?

A

A single copy of P53 is enough to prevent excessive tumour formation

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

Main characteristics of cancer cella/

A
  • Can rapidly proliferate
  • Can prevent induction of apoptosis
  • Can prevent cell cycle arrest
  • Can develop their own blood supply= angiogenesis
  • Can spread to invade other locations of the body via metastasising
  • Can rapidly develop mutations
  • Can evade immune detection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do cancers develop?

A
  1. Neoplastic progression: mutations arise e.g. in tumour suppressor genes
  2. There is clonal expansion. Rapid excessive proliferation and selection
  3. The tumour cells move to different parts of the body (metastasis) or can even invade other individuals (transmissible tumours)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where do many tumours tend to metastasise?

A
  • Liver
  • Bone marrow
  • Lung
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why do many tumour cells metastasise to certain locations?

A

Due to the overexpression of CXCR4 on the surface of tumour cells, causes them to move to locations expressing high levels of CXCL12 ligand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is required for cancers to be transmissible?

A
  • Require a means of transmission

- Require an ability to evade immune detection

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

What prevent transmissible cancers in humans?

A
  • MHC variation between individuals. Very good ability of our immune systems to discriminate self from non-self
  • No route of direct transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which species can transmissible cancers be observed in?

A

Tasmanian devils
Syrian hamsters
Canines
Marine bivalves

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

Tasmanian devils were found in Australia up until?

A

500 years ago

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

Tasmanian devils now have a restricted distribution where?

A

Mainland tasmania

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

What is DFTD?

A

Devil Facial Tumour Disease

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

When was DFTD first recognised?

A

1996

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

DFTD has spread through?

A

85% of the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

DFTD causes death within?

A

6 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Death is caused by?

A

Organ failure
Metastasis
Starvation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

We expect the natural population to go extinct within the next?

A

20-30 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How did they recognise this was not caused by a virus but through allograft transmission?

A

Identical karyotypes between the tumours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What was the common karyotype compared to normal cells?

A

Normal cells: 14 chromosomes

Tumour cells: 13 chromosomes and non sex chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the karyotype?

A

The number and appearance of chromosomes in a eukaryotic nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What else showed that the tumours were of the same origin?

A

Microsatellite analysis showed that the tumours from different devils were more closely related to eachother than they are to other devils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the original origin of these cells?

A

From a female devil
20 years ago
Schwann cell origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How did they know the tumour cells are of neural cell origin?

A

Transcriptome of the tumour cells was very similar to the transcriptome of schwann cells

27
Q

Where does DFTD cause tumours?

A

On the face

28
Q

How is DFTD transmissible?

A

Biting during feeding and sex

29
Q

How does DFTD evade immune detection?

A
  • Has the same MHC alleles as the devils
  • Devils show low MHC diversity, probably due to the population bottle neck and due to high levels of inbreeding in fragmented populations
30
Q

Why did they believe DFTD would not spread from Eastern to Northwestern populations?

A

As they showed varying MHC alleles
More MHC diversity
Skin allografts were rapidly rejected between the two populations

31
Q

Did the northwestern devils catch DFTD?

A

Yes

32
Q

How did the northwestern devils catch DFTD if skin allografts were rejected?

A

The DFTD was mutating to develop immune evasion techniques

33
Q

What methods of immune evasion?

A

Down regulation of MHC-I to avoid T cell detection (reduced expression of genes associated with antigen processing and expression e.g. TAP1 and TAP2)
Reduced recognition by NK cells

34
Q

Why was the DFTD observed in the Northwestern populations less virulent?

A

It was strain 2 which is less virulent and tetraploid

There are different strains of DFTD, different karyotypic strains

35
Q

Why was strain 2 less virulent?

A

Tetraploid which means it grows slower as it takes longer to replicate its DNA
As the tumours grow slower the devils live for longer and virulence is reduced

36
Q

Why is lower virulence associated with directly transmitted diseases unsurprising?

A

As for directly transmitted diseases there is a transmission-mortality tradeoff. Lower virulence is selected for and expected as it is more likely to be transmitted

37
Q

What is DFT2?

A

A second transmissible neoplastic cell line which was discovered

38
Q

DFT2 origin?

A

Male devil

39
Q

DFT1 origin?

A

Female devil

40
Q

Discovered of DFT2 showed that?

A

Multiple transmissible tumours can arise

41
Q

How can we prevent the extinction of devils?

A
  • Creating captive bred insurance populations
  • Developing a vaccine
  • Culling of infected devils
42
Q

Why might we think that DFTD will evolve to become non-harmful?

A

Due to CTVT in canines, this has almost no virulence

43
Q

What transmissible tumours were seen in laboratory syrian hamster populations?

A

Contagious reticulum cell sarcoma

44
Q

Contagious reticulum cell sarcoma was spread via?

A

Mosquitos

Social contact

45
Q

CTVT?

A

Canine Transmissible Venereal Cancer

46
Q

CTVT is what type of cancer?

A

Histiocytic tumour

47
Q

Where do the tumours grow?

A

Genitalia

48
Q

Origin?

A

Wolf

~11,000 years ago

49
Q

CTVT spreads via?

A

Sexual transmission

50
Q

How does CTVT overcome host immunity?

A

Developed immune evasion mechanisms:

  • Down regulation of MHC
  • Production of immunosupressive cytokines
51
Q

Is CTVT virulent?

A

Not very virulent
Self-limiting
Regressive

52
Q

Does CTVT metastasise?

A

Only in immunosuppressed canines

53
Q

CTVT is very responsive to?

A

Chemotherapy

54
Q

Transmissible cancer in bivalves is?

A

Haemic cancer

55
Q

Haemic cancer?

A

Haemocytes

Leukaemia like

56
Q

What cancer is CTVT?

A

Histiocytic tumour

57
Q

What transmissible cancer is present in bivalves?

A

Haemic neoplasm

Hamocytes, leukaemia like

58
Q

How are haemic neoplasms transmitted?

A

In the water

Via filter feeding

59
Q

How are they not rejected?

A

Do not believe they have MHC

Immune systems have yet to be fully characterised

60
Q

In bivalves the tumours can spread from?

A

One species to another

61
Q

Example of spread from one species to another?

A

Spread from pallet clam to a golden carpet shell clam

62
Q

The pallet clams are resistant to the?

A

Haemic neoplasm

63
Q

Transmissible cancers only occur in humans in which cases?

A
  • Immune suppression due to organ transplant

- From mother to child during development: Placental transmission

64
Q

In order for placental transmission?

A
  • Mother must have homozygotic HLA loci
  • Developing immune system may be tolerized by early exposure
  • Deletion of different HLA loci

Parasitology (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions