Behaviours of Tumours Flashcards
what are the two characteristics of a malignancy
invade and destroys adjacent normal tissue
metastasis - spreads from site of origin forming new tumours
why is invasion from tumours capable
increased motility, decreased adhesion, production of proteolytic enzymes and mechanical pressure
describe how there is less adhesion in cancer cells
mutation in E-cadherin leads to loss of cell to cell adhesion and contact inhibition
changes in integrins stops cell-matrix adhesion
change from epithelial cell to mesenchymal cells makes them loosely connected and able to migrate
how does the production of proteolytic enzymes enable invasion of tumours
matrix metalloproteinases degrade ECM and allow local invasion
how does mechanical pressure promote spread of cancer
uncontrolled proliferation forms mass which occludes vessels and causes atrophy and allows spread along line of least resistance
what are the two types of bone metastases
bone metastasis spread from there to breast, prostate, lungs, kidney, thyroid
can be lytic (destroy the bone) or sclerotic (fill the bone with cells)
where do lung cancer most commonly spread
to brain and adrenal metastases
what are the 5 stages of tumour metastases
detachment from site and invasion intravasation (into vessel) survival against host defences adherence onto vessel wall and extravasation growth and angiogenesis
what is the mechanical hypothesis of metastasis
dictated by anatomy eg lymphatic drainage
what is the seed and soil hypothesis
when a plant goes to seed its seeds are carried in all directions but they can only live and grow if they fall on congenial soil (Stephen paget)
ie the tissue environment is important - influences organ selectivity
how does angiogenesis differ normally and pathologically
normally important fro development and healing
pathologically important for metastases to grow larger
what are common promoters of malignancies
VEGF, PDGF, TGFB - encourage angiogenesis and cause an imbalance
why do we stage and grade cancer
determine prognosis
decide how to treat the tumour
research
what is the difference between staging and grading a cancer
stage - how advanced is the tumour, has the cancer spread and to what extent
grade - how aggressive is the tour itself and how different foes it look from the origin of the tissue
what system is use to stage tumours
TMN system
T - tumour - size of primary tumour
M - metastases - presence and extent of of distant metastases
N - nodes - presence ad number of lymph nodes metastases
