behaviour of tumours

Question 1

what is hypertrophy

Answer 1

enlargement in individual cell size

Question 2

what is hyperplasia

Answer 2

increase in the number of cells

Question 3

what is metaplasia

Answer 3

the replacement of mature tissue types

Question 4

what is dysplasia

Answer 4

abnormality indicating precursor change of malignancy

Question 5

what is anaplasia

Answer 5

failure to differentiate, malignancy

Question 6

how do malignant tumours behave?

Answer 6

invasion
metastasis
angiogenesis

Question 7

what is the difference between invasion and metastasis

Answer 7

invasion, invades adjacent normal tissue and destroys normal tissue whereas in metastasis, tumour spreads from site of origin to distant sites and forms new tumours in these new areas

Question 8

what % of adult cancer patients have metastatic disease?

Answer 8

half of all cancer patients

Question 9

what % of breast cancer patients have metastatic disease?

Answer 9

1/3 of breast cancer patients

Question 10

what % of patients with basal cell carcinoma have metastatic disease

Answer 10

essentially no patients have metastatic disease

Question 11

how do epithelial cells start to invade and migrate in cancer

Answer 11

epithelial cells gain mesenchymal properties, mesenchymal cells are loosely connected are able to migrate. this means the epithelial cells with the newly gained function can invade and migrate.

Question 12

what is the role of proteolytic enzymes in cancer?

Answer 12

they degrade the ECM and therefore promote local invasion

Question 13

which proteolytic enzymes degrades which type of collagen

Answer 13

interstitial collagenases degrades collagen types 1, 11, 111

gelatinises degrades collagen type IV, gelatin

stomolysins degrades collagen type IV, proteoglycans

Question 14

what is the role of proteolytic enzymes in normal tissue regulation and how can proteolytic enzymes cause cancer?

Answer 14

normal tissue regulation is a balance between matrix metalloproteinases and tissue.

cancer favours ECM breakdown. therefore it increases matrix metalloproteinases and decreases tissue inhibitors of metalloproteinases and therefore favours ECM breakdown and therefore promotes local invasion

Question 15

what are the routes for metastasis

Answer 15

lymphatic - distant or local lymph nodes

blood - liver, lungs, bone and brain

transcoelomic - across peritoneal, pleural, pericardial cavities or in CSF

Implantation - spillage of tumour during biopsy/surgery

Question 16

what are the stages of metastasis

Answer 16

intravasation

detachment invasion

survival against host defences

adherence extravasation

growth

Question 17

what is the pattern of metastasis in carcinomas

Answer 17

in carcinomas, lymphatics spread first

Question 18

what is the pattern of metastasis in sarcomas

Answer 18

blood spreads first

Question 19

what is the pattern of metastasis in bone metastases

Answer 19

spreads to breast, prostate, lung, kidney and thyroid

Question 20

what is the pattern od metastasis in transcoelomic metastasises

Answer 20

ovarian

Question 21

what is the mechanical hypothesis in patterns of metastasis

Answer 21

the mechanical hypothesis is directed by anatomy e.g. lymphatic drainage, liver mets in GI cancer

Question 22

what is the seed and soil hypothesis in patterns of metastasis?

Answer 22

when a plant goes to seed, its seeds are carried in all directions; but they can only live and grow if they fall on congenial soil.

Question 23

when is angiogenesis particularly important.

Answer 23

angiogenesis is essential if metastases are to grow larger than 1-2 mm

Question 24

why stage and grade cancer?

Answer 24

determine prognosis - survival time, quality of life

decides how to treat the tumour

research- it allows us to compare therapies or prognostic factors

Question 25

how are tumours staged

Answer 25

tumours are staged using TMN system ]

T- size +/- extent of primary tumour
M- prescience and extent of distant metastases
N -prescence and number of lymph Node metastases

Question 26

By what basic mechanisms do tumour cells start to invade local tissues?

Answer 26

1) Increased motility
2) Decreased adhesion
3) Mechanical pressure
4) Production of proteolytic enzymes

Question 27

What are the 2 classes of adhesion molecule which are lost in malignant cells?

Answer 27

Cell to cell adhesion molecules - cadherins

Cell to matrix adhesion molecules - integrins

Question 28

What changes occur leading to a reduction in adhesion of malignant cells?

Answer 28

Mutation of E-cadherin in malignant cells leads to loss of cell-cell adhesion and contact inhibition
Changes in integrin expression in malignant cells lead to decreased cell-matrix adhesion

Question 29

Are metalloproteinases produced by healthy cells?

Answer 29

Yes, they play a role in normal tissue regulation and are balanced by tissue inhibitors of metalloproteinases

Question 30

What is the role of metalloproteinases in normal tissue regulation?

Answer 30

Needed to mop up collagen and remodel tissues etc.

Question 31

How does mechanical pressure contribute to invasion?

Answer 31

Uncontrolled proliferation forms a mass
Pressure occludes vessels
Get pressure atrophy
Tumour spreads along the line of least resistance

Question 32

What are the cell to cell adhesion molecules?

Answer 32

cadherins

Question 33

What are the cell to matrix adhesion molecules?

Answer 33

integrins

Question 34

What is the difference between epithelial cells and mesenchymal cells?

Answer 34

Epithelial cells - tightly connected, polarised and tethered

Mesenchymal cells - loosely connected, able to migrate

Question 35

What are matrix metalloproteinases?

Answer 35

Enzymes responsible for the degradation of most extracellular matrix proteins

Question 36

What does the transcoelomic route of metastasis mean?

Answer 36

Across peritoneal, pleural, pericardial cavities or in CSF