Lecture 7 - tumour microenvironment 2

Question 1

What are the 2 mechanisms by which cancer can spread through the body?

Answer 1

Invasion and metastasis

Question 2

What is a tumour’s capacity to metastasise based on?

Answer 2

The whole tumour cell population and how many havethe potential to metastasise

Question 3

What is early metastasis?

Answer 3

• Evidence suggests cells can disseminate remarkably early from apparently noninvasive premalignant lesions
• May form micrometastases though their ability to colonise and develop into significant macrometastases is unproven

Question 4

Tumours from what tissue are more likely to metastasise?

Answer 4

Melanomas

Question 5

What are circulating tumour cells? (CTCs)

Answer 5

cancer cells transitting in blood/lymphatic vessels following intravasation

Question 6

Why are CTCs inefficient?

Answer 6

In a hostile environment

Question 7

Why are vessels a hostile environment to CTCs?

Answer 7

• Lack of stromal support

- Hydrodynamic shear forces

Question 8

What can CTCs do to protect themselves in vessels?

Answer 8

Recuit platelets and form microthrombi

Question 9

What did Stephen Paget do in 1889?

Answer 9

Analysed 900 autopsy records with different primary tumours and identified a non-random tissue distribution of secondary tumours.
- Concluded some types of tumour have an affinity for specific organ environments

Question 10

Where are secondary tumours most likely to end up?

Answer 10

The first pass organ - first organ downstream in circulatory system

Question 11

What could cause a moving cancer cell to stop at a specific point?

Answer 11

Endothelial cells lining blood vessels in different organs express different adhesion molecules
Tumor cells expressing corresponding receptor may arrest in specific locations