Flashcards in MOD Deck (186)
In order to invade at a primary site what changes must tumour cells undergo and how?
Alter adhesion - e-cadherin and integrin must change
Lyse basement membrane - alter niche cells to cause proteolysis
Change cell mobility - alter cytoskeleton such as. Changes to rho family proteins
What are the changes in a primary epithelial malignant tumour preparing for metastasis called?
Epithelial to mesenchymal transition
What is the difference between e-cadherin and integrin?
E-cadherin is cell to cell anchoring
Integrin is cell to basement membrane anchoring
What routes can tumours spread?
What is the easiest route for metastasis? Why?
Lymphatics - thin membranes
What are the common sites of secondaries (very generally!) in each of the three routes of metastasis?
Lymph - regional lymph nodes
Blood - first capillary bed reached
Transcoelomic - gravity assisted (eg. Pouch of Douglass)
What explains variation in then common rules of tumour metastasis distribution?
Seed and soil theory - metastases can only settle where the niche is correct (e.g. Why bronchial tumours metastasis are found in the adrenals but not the kidneys)
What is the main route of carcinoma spread
What is the main route of sarcoma spread?
What common cancers cause bone mets?
What is growth at secondary site of cancer also known as?
What is the theory behind cancer relapse?
Formation of micrometastases at secondary sites that dont develop can reactivate
What are causes of micrometastases dormancy?
Failure of angiogenesis
What are local clinical effects of neoplasms?
Direct invasion and tissue destruction
Blockage of tubes and ducts
Compression of adjacent structures
What are the systemic effects of neoplasm?
Increased tumour burden - weight loss, malaise, immunosuppression, thrombosis
Hormone production (especially well differentiated tumours, therefore more common in benign tumours)
Poorly understood issues such as clubbing, fever, myositis
What are extrinsic causes of cancer?
Environmental factors (e.g. UV exposure)
Lifestyle factors (e.g. Smoking, overweight, alcohol, low exercise, low fruit and veg)
What are examples of intrinisic risk factors for cancer?
What are the three categories of extrinsic carcinogens?
What are the typical characteristics of chemical carcinogens?
Long delay between exposure and cancer
Increased risk with increased dose
Can be organ specific
Give some examples of chemical carcinogens
Asbestos - mesothelioma
Tobacco - bronchial carcinoma
What is the term for a chemical which is a initiator and a promotor of cancer?
What are the types of nuclear radiation?
What are the electromagnetic carcinogenes?
Which radiationn carcinogens cause ionisation?
Alpha, beta and gamma as well as xrays.
Which electormagentic carcinogen has the shortest wavelenght?
How does ionising radiation work?
Strips electrons off atoms
What are examples of direct and indirect damage from radiation?
Direct - alteration of bases etc
Indirect - production of ROS
What are direct and indirect carcinogenic mechanisms of infection?
Direct - influencing protooncogene and tsg
Indirect - cause chronic injury necessitating regeneration (acting as a promotor)
How does HPV cause cancer?
Expresses proteins E6 (inhibits p53) and E7 (inhibits RB)