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EMS - Mechanisms of disease > Behaviour of tumours > Flashcards

Flashcards in Behaviour of tumours Deck (26):
1

What are the different types of tumour behaviour?

Invasion, metastasis and angiogenesis

2

What is invasion?

- Invades adjacent normal tissue
- Destroys normal tissue

3

What is metastasis?

Spreads from site of origin to distant sites and forms new tumours in these new areas

4

What are the features of invasion?

- Increased motility
- Decreased adhesion
- Production of proteolytic enzymes
- Mechanical pressure

5

What are cadherins and what is their role in cancer?

Cell to cell adhesion molecules.

Mutation of E-cadherin leads to loss of cell-cell adhesion and contact inhibition

6

What are integrins and what is their role in cancer?

Cell to matrix adhesion molecules.

Changes in integrin expression lead to decreased cell-matrix adhesion

7

What is the difference between normal epithelial and mesenchymal cells.

- Epithelial cells are tightly connected, polarised and tethered
- Mesenchymal cells loosely connected, able to migrate

8

What is epithelial-mesenchymal transition?

In cancer epithelial cells gain mesenchymal properties and can invade and migrate.

9

Which proteolytic enzymes are active in cancer?

Matrix Metalloproteinases - degrade extracellular matrix.

Interstitial collagenases, gelatinases, stomolysins

10

What are the potential routes of metastasis?

Lymphatic
- Distant or local lymph nodes

Blood
- Liver, lungs, bone, brain etc

Transcoelomic
- Across peritoneal, pleural, pericardial cavities or in CSF

Implantation
- Spillage of tumour during biopsy/surgery

11

What are the stages of metastasis?

1. Intravasation
2. Detachment/invasion
3. Survival against host defences
4. Adherence and extravasation
5. Angiogenesis
6. Growth

12

By which route do carcinomas typically spread?

Lymphatic (first)

13

By which route do sarcomas typically spread?

Blood (first)

14

Which cancers are most commonly associated with bone mets?

Breast
Prostate
Lung
Kidney
Thyroid

15

Which cancer is most commonly associated with transcoelomic spread?

Ovarian

16

Which cancer is most commonly associated with brain and adrenal mets?

Lung

17

What is the mechanical hypothesis?

Dictated by anatomy eg, lymphatic drainage. Liver mets in GI cancer

18

What else is important in metastasis?

- Tissue environment is important – influences organ selectivity for metastases
- Metastatic cells can remain dormant for years

19

Why is angiogenesis essential?

If metastases are to grow larger than 1-2mm

20

Which growth factors are promoters of angiogenesis?

VEGF
PDGF
TGFβ

21

What factors are inhibitors of angiogenesis?

ECM proteins
Thrombospondin
Canstatin
Endostatin

22

What is stage?

How advanced is the tumour? Has the cancer spread and if so what is the extent of spread.

23

What is grade?

How aggressive is the tumour? How different does it look from tissue of origin.

24

How are tumours staged?

Tumours are staged using TMN

T = Size +/- extent of primary tumour
M = Presence and extent of distant metastases
N = Presence and number of lymph node metastases

Can be combined to give an overall stage for the tumour (I-IV)

Each organ has an individual TMN system
Stage can be clinical, pathological or radiological

25

What is the Dukes staging for colorectal cancer?

A = invades into, but not through bowel wall
B = invades through the bowel wall but with no lymph node metastases
C = Local lymph nodes involved
D = Distant metastases

26

How is grading determined?

- Differentiation – how much does the tumour resemble tissue it originates from

- Nuclear pleomorphism and size

- Mitotic activity

- Necrosis