Neoplasia 2 Flashcards
Why are metastasis the most lethal feature of a malignant neoplasm?
More metastisis increases the tumour burden
Do benign tumours metastasise?
No
What 3 steps are needed for a malignant cell to move from a primary to secondary site?
1) Grow and invade at the primary site
2) Enter a transport system and lodge at a secondary site
3) Grow at the secondary site and form a new tumour i.e. COLONISATION
What 3 things are needed for carcinoma cells to invade surrounding tissues?
1) Adhesion
2) Proteolysis
3) Motility
What is another name for carcinomas invading surrounding tissues?
Epithelial-to-Mesenchymal Transition (EMT)
Explain how the expression of cell features change in each of the steps of EMT
1) Adhesion- reduction in E-cadherin expression (bind cells to each other) and altered integrin expression
2) Proteolysis - Matrix Metalloproteinases (MMPs) degrade the basement membrane and stroma to invade
3) Motility- changes in the actin cytoskeleton by non-neoplastic cells providing growth factors and proteases
What 4 things make up a niche?
- Stroma
- Fibroblasts
- Endothelial Cells
- Inflammatory cells
Give 3 ways in which malignant cells can reach distant sites?
1) via blood
2) via lymphatics
3) via fluid in the body cavities (pleura, peritoneal, pericardial and brain ventricles)
What is travel by the fluid in body cavities known by?
Transcoelomic Spread
Which step of growing at a secondary site is the most difficult for cancer cells?
Colonisation
What are micro metastases?
Surviving microscopic deposits of cells that fail to colonise
What 3 things could cause a micrometases to become dormant?
- immune attack
- reduced angiogenesis
- a hostile secondary site
What 2 things can determine the site of a secondary tumour?
1) regional training of blood, lymphatics to coelomic tissue
2) Seed and soil phenomenon
How can you predict the site of a secondary metals using regional drainage?
- Lymphatics- will be the next regional lymph node
- Blood- will usually be the next capillary bed, usually in the lungs or the liver
- Coelum- will spread to other areas in the coelomic space (gravity dependent) or to adjacent organs
Briefly explain the seed and the soil phenomenon
The seed is the malignant cells
The soil is the niche i.e. the right conditions are needed for the tumour to grow at the secondary site
