invasion & metastasis

Question 1

how does cancer occur

Answer 1

A single cell acquires mutations to become cancerous, and then this divides and divides until all of the healthy cells have been replaced with cancerous cells.

Question 2

define in situ neoplasia

Answer 2

represents the earliest form of malignant progression and is characterized by localization limited to the compartment corresponding to the cell of origin

it may progress to invasive disease

Question 3

what does in situ neoplasia only apply to

Answer 3

epithelial neoplasms

Question 4

describe basement membrane in in situ neoplasia

Answer 4

it is intact

Question 5

what does screening of in situ neoplasia allow

Answer 5

Screening may allow detection and treatment before development of carcinoma

Question 6

define carcinoma in situ

Answer 6

a malignant epithelial neoplasm that has not yet invaded through the original basement membrane

Question 7

define Invasive carcinoma:

Answer 7

a carcinoma that has breached the basement membrane – it can now spread elsewhere

Question 8

define micro-invasive carcinoma

Answer 8

has breached the basement membrane but hasn’t invaded very far away from the original carcinom

Question 9

what is invasion

Answer 9

The defining feature of a malignant neoplasm

Question 10

what does invasion allow

Answer 10

Enables the neoplastic cells to spread directly through tissue and gain access to blood vessels and lymphatic channels

Question 11

what does invasion depend on

Answer 11

• decreased cellular adhesion
• abnormal cellular motility
• the production of enzymes with a lytic effect on the surrounding tissues

Question 12

define metastasis

Answer 12

the process by which a malignant tumour spreads from its primary site to produce secondary tumours at distant sites

Question 13

what can metastasis occur via

Answer 13

blood vessels
lymphatics
across body cavities
along nerves
or as a result of direct implantation of neoplastic cells during a surgical procedure

Question 14

describe metastatic cascade

Answer 14

1. Detachment
2. Invasion
   -invade through the basement
   membrane
3. Intravasation
   -Collagenases
   -Cell motility
4. Evasion of host defences
   -Aggregation with platelets
   -Shedding of surface antigens
   -Adhesion to other tumour cells
5. Arrest
6. Extravasation
   -Adhesion receptors
   -Collagenases
   -Cell motility
7. Vascularisation

Question 15

how does growth occur at the metastatic site

Answer 15

using autocrine growth factors

Question 16

what happens once the tumour reaches 1mm in diameter

Answer 16

they begin to grow their own blood vessels (angiogenesis).

`

Question 17

give 2 angiogenesis promoters

Answer 17

Vascular endothelial growth factors
Basic fibroblast growth factor

Question 18

give 3 angiogenesis inhibitors

Answer 18

Angiostatin, endostatin, vasculostatin

Question 19

give 4 routes of metastasis

Answer 19

1. It can invade the arterial side if it grows large enough and breaks off
2. Haematogenous
3. lymphatic
4. Trans-coelomic

Question 20

describe the haematogenous route of metastasis

Answer 20

by the blood stream – forms secondary tumours in organs perfused by blood that has drained from a tumour

Question 21

describe the lymphatic route of metastasis

Answer 21

lymph channels – form secondary tumours in the regional lymph nodes

Question 22

describe the trans-coelomic route of metastasis

Answer 22

pericardial and peritoneal cavities where this invariably results in a neoplastic effusion

Question 23

what tumours more commonly metastasise to the lung

Answer 23

sarcomas and any common cancers

Question 24

what tumours more commonly metastasise to the liver

Answer 24

colon, stomach, pancreas, and carcinoid tumours of intestine

Question 25

what tumours more commonly metastasise to bone

Answer 25

prostate, breast, thyroid, lung and kidney