14. Neoplasia 2 Flashcards
What is tumour burden?
Refers to the total amount of cancer tissue in the body
What are the most lethal features of malignant neoplasms?
Invasion and metastasis
Compare invasion and metastasis
Invasion:
Breach of the basement membrane with progressive infiltration and destruction of the surrounding tissues
Metastasis:
Spread of tumour to sites that are physically discontinuous from the primary tumour. Unequivocally marks a tumour as malignant
What are the 3 stages of invasion and metastasis?
(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 to form a new tumour
What is neoplastic growth at a secondary site called?
Colonisation
How efficient in invasion and metastasis?
whole process is inefficient - THE CELLS MUST EVADE DESTRUCTION BY IMMUNE CELLS
What 3 alteration occur in cancer cells for invasion to occur, what is this change called and why?
INVASION INTO SURROUNDING TISSUE BY CARCINOMA CELLS REQUIRES:
altered adhesion, stromal proteolysis and motility
Epithelial-to-mesenchymal transition (EMT): three changes together create a carcinoma cell phenotype that sometimes appears more like a mesenchymal cell than an epithelial cell. the 3 changes allow the cancer cell to detach from other cells and invade
What does altered adhesion in malignant cells involve?
Between malignant cells: reduction on E-cadherin expression
Between malignant cells and stromal protein: changes in Integrin expression
What does altered stromal proteolysis in malignant cells involve?
Altered expression of proteases, notably matrix metalloproteinases (MMPs)
• Malignant cells take advantage of nearby non-neoplastic cells, which provide growth factors and proteases, , WHICH TOGETHER FORM A CANCER NICHE
Why is altered stromal proteolysis important?
Cells must degrade basement membrane and stroma to invade
What does altered motility of malignant cells involve?
Involves changes in the actin cytoskeleton
What is a cancer niche?
a supportive network for cancer cells to invade:
a combination of stroma, fibroblasts, endothelial cell, inflammatory cells
How does signalling through integrins occur in malignant cells?
Via small G proteins such as members of Rho family
What are the 3 different routes malignant cells can be transported?
(1) blood vessels via capillaries and venules;
(2) lymphatic vessels;
(3) fluid in body cavities
Give examples of fluid filled body cavities that malignant cells can metastasise through.
pleura, peritoneal, pericardial and brain ventricles
What is metastasise through fluid filled cavities called?
transcoelomic spread
What is the greatest barrier to successful metastasis of malignant cells?
Failed colonisation
What are micrometastases?
Surviving microscopic deposits of malignant cells that fail to grow at a secondary site
- tumour dormancy