Outline of disease process Flashcards
What are the 3 types of carcinogens, responsible for the initiation stage of cancer?
Chemical
Physical
Viral
What is the main physical carcinogen?
Ionising radiation
What 3 ways could a physical carcinogen initiate cancer?
Chromosome translocation
Gene amplification
Oncogene activation
What causes the promotion of cancers?
Growth factors
Oncogenes
Describe the function of growth factors in promotion
Bind to cell membrane receptors
Stimulate activation of intracellular signal transduction pathways
Signal causes (further) oncogene activation and more GF and GFRs are synthesised
What is the difference between autocrine and paracrine stimulation?
Autocrine - growth factor binds to GFR on it’s own cell - further stimulates it’s own cell
Paracrine - growth factor binds to another cells receptor and stimulates that cell
What do tumour suppressor genes normally control?
DNA repair
Apoptosis
Differentiation
What is the main tumour suppressor gene?
G1/S checkpoint control gene
Describe the process of invasion and metastasis
Tumour invades adjacent tissue through basement membrane
Moves into ECM/CT/surrounding tissue
Invades blood vessels - intravasation
Extravasation in distant organ/tissue - cells are ‘arrested’
Tumour forms - metastasis
For what reason must the extracellular matrix be broken down for tumour growth to occur?
To allow angiogenesis to take place
Tumour needs a blood supply so blood vessels must form
Growth factor orientated treatment targets what stage of the cancer process?
Promotion
Describe how cancer cells are able to hide from our immune system?
T cells have PD1 receptor
Tumour cells have the ligand for this - PDL-1 on their surface
Interaction of these suppresses T cell attack
By blocking PD1 or PDL-1, we can cause an immune response
