outline of disease

Question 1

Describe the principles of ‘staging’ in cancer.

Answer 1

1-. initiation: due to exposure to a carcinogen( chemical, physical, virological
2. promotion:
- tumour suppressor genes which are in regulating DNA transcription, DNA repair and apoptosis are switched off
-proto-oncognes: transform genes
-growth factors: Bind to cell membrane and stimulate intracellular signal transduction processes.
Can occur either by autocrine- cell produces growth factors and has growth factor receptors- or paracrine- growth factors are produced nearby.
3. progression: metastasise- invades through basement membrane into connective tissue/ECM and then into blood vessel.
-facilitated by enzymes in the ECM ( plasmin, cathepsxn, matrix metalloprotein) and in cell adhesion ( cahedrins, CD44, integrins)
-angiogenesis
-intravasatation/extravasatation

Question 2

Explain the importance of genetic changes in cancer.

Answer 2

Link tumour suppression, protooncogene, metastasis.
PD1 receptors present on T-cells
PDL1 receptors present on tumour cells.
When they interact they suppress the immune system so tumour cells can grow.
-Normal cell exposed to carcinogen becomes transformed- presents tumour antigens and danger signals.
-can either be eliminated through extrinsic tumour suppression
-can undergo dormancy and further editing which leads to removal of tumour antigen so they can escape and undergo growth.

Question 3

Describe modalities of therapy currently available.

Answer 3

Can use the fact that PD1 and PDL1 are involved in the process to create inhibitors which work on both.