Cancer Invasion and Metastasis Flashcards Preview

SSC- Biology of Cancer > Cancer Invasion and Metastasis > Flashcards

Flashcards in Cancer Invasion and Metastasis Deck (52)
1

When is a tumour considered to be benign? 

If the neoplastic cells are clustered in a single mass

2

When is a tumour considered to be malignant? 

Once the tumour has undergone metastasis 

3

How many different types of tumours are there? 

As many as there are different types of human cells - 200 

4

What does the grouping of a tumour depend on? 

The tissue of origin 

There is increasing use of molecular definitions to stratify cancers 

5

What are benign tumours of epithelial tissues called? 

  • Adenomas
  • Papillomas

 

6

What are malignant tumours of epithelial cells called? 

Carcinomas

7

What are benign connective tissue tumours called? 

  • Lipomas
  • Fibromas
  • Haemangiomas

 

8

What are malignant tumours of connective tissue called? 

Sarcoma

 

9

What are benign tumours of lymphoid tissue called? 

Lymphoid hyperplasia 

10

What are malignant tumours of lymphoid tissue called? 

Lymphoma

11

What are malignant tumours of haemopoietic tissues called? 

Myeloid proliferations

12

What are malignant tumours of haemopoietic cells called? 

Leukaemia 

13

What are benign tumours of germ cells called? 

Teratomas 

14

What are malignant tumours of germ cells called? 

Germinoma

15

Which of the hallmarks of cancer relate to metastasis? 

  • Induction of angiogenesis
  • Activating invasion and metastasis

 

16

What can be determined about tumour metastasis from studies of colon carciogenesis? 

Cancer is a multi-hit disease, with accumulation of genetic changes, and the transition to metastasis occurs at the end, once a lot of damage has already been done 

17

What are the steps in the formation of a metastasise? 

  1. Primary tumour formation
  2. Localised invasion
  3. Intravasation
  4. Transport through circulation
  5. Arrest in microvessels of various organs
  6. Extravasation
  7. Formation of micrometastasis
  8. Colonisation and formation of macrometasis

 

18

What allows localised invasion of a tumour? 

Formation of blood vessels

19

What happens in tumour intravasation? 

Interaction of tumour with platelets, lymphocytes, and other blood components 

20

What must be done at all stages of metastasis? 

Evasion of the immune system 

21

What allows metastasis to be successful despite it being an inefficient process? 

Sheer force of numbers - there are potentially millions of cells circulating

22

What % of disseminated tumour cells survive to be solitary cells in a secondary organ? 

80%

23

What are the potential fates for solitary cells that get into a secondary organ? 

  • Proliferate
  • Viable but dormant
  • Die 

 

24

What % of disseminated tumour cells initiate growth into micrometastases? 

2%

25

What % of disseminated tumour cells persist to grow into macrometastases? 

0.02%

 

26

Give an example of where other types of cells in the microenvironment are involved in metastasis

Tumour associated macrophages promote breast cancer metastasis 

27

How are macrophages involved in breast cancer metastasis? 

A paracrine loop between tumour cells and macrophages is required for tumour cell migration in mammary tumours 

28

Describe the paracrine loop between tumour cells and macrophages required for cell migration in mammary tumours

Tumour cells express CSF-1, which binds to CSF-1 receptor on macrophages and allows them to proliferative and survive. Macrophages express EGF, which binds EGF-receptors on tumour cells 

29

Why is the loss of cell to cell adhesion important in tumour cell metastasis? 

Epithelial cells are very tightly organised with strong cell-cell adhesion, which has to be detatched in order for cells to move

30

What are the different types of adhesions that join cells? 

  • Tight junction
  • Adherens junction
  • Desmosome

 

31

What are cadherins? 

Key adherence molecules that span the plasma membranes of cells, and allows attachment of 1 cadherin to another

32

What is cadherin adhesion regulated by? 

Calcium 

33

Give an example of a cancer where E-cadherin expression is important

Abberrant or absent E-cadherin expression is associated with aggressive bladder cancer 

34

What other features of cancers is aberrant or E-cadherin expression associated with? 

  • Advanced tumour stage
  • Tumour de-differentiation
  • Lymph node metastasis

 

35

How is epithelial to mesenchymal transition activated? 

Different signalling pathways; STAT3 pathway, FGF pathway, ER pathway, TGFß pathway

 

 

36

Broadly, how do signalling pathways activate epthelial to mesenchymal transition 

The signalling molecule induces the expression of key transcription factors - Twist, Snail, SIP1. These transcription factors suppress E-cadherin expression, and increase mesenchymal markers 

37

What are the categories of migration mechanisms? 

  • Collective
  • Individual

 

38

What are collective migration mechanisms mainly linked to? 

Loss of E-cadherin expression 

39

What migration strategies are employed in collecting migration? 

  • Multicellular strands/sheets
  • Cluster/cohorts 

 

40

Give two examples of tumours that migrate in clusters/cohorts

  • Epithelial cancer 
  • Melanoma

 

41

Give two examples of tumours that migrate in multicellular strands/sheets

  • Epithelial cancer
  • Vascular tumours

 

42

What are individual migration mechanisms predominantly associated with? 

Integrin mechanisms and secretions of proteases 

43

What migration strategies are employed by the individual migration method? 

  • Ameoboid
  • Mesenchymal (single cells)
  • Mesenchymal (chains)

 

44

Give three tumour types that migrate by the ameoboid strategy

  • Lymphoma
  • Leukaemia
  • SCLC

 

45

Give three tumour types that migrate by the mesenchymal mechanism

  • Fibrosarcoma
  • Glioblastoma
  • Anaplastic tumours 

 

46

What are the steps in mesenchymal migration? 

  1. Protrusion
  2. Adhesion
  3. Translocation
  4. Retraction 

 

47

What is the protrusion stage of mesenchymal migration associated with? 

Key enzymes at the leading edge 

48

What are focal adhesions?

Key complexes of proteins that allow attachment of cells to the extracellular matrix

49

What is vinculin? 

A component of focal adhesions that act as specific attachment pads

50

What do integrins consist of? 

  • Transmembrane receptors
  • 24 heterodimers - 18 alpha and 8 beta subunits

 

51

What does the ECM consist of? 

  • Mesh of fibrous proteins - laminins, collagens, fibronectin, elastin
  • Glycosaminoglycasns

 

52