Module 3 - Chapter 10 - Metastasis Flashcards
Metastasis
Spread of cancer cells from the site of the original tumour to distant tissues and organs through the body
What is the defining characteristic of cancer and common cause of death from cancer?
metastasis
What percentage of individuals with breast Ca mets are still alive 5 years after diagnosis?
30%
What can initiate the metastatic process?
= Change in the tumour microenvironment including stromal cell adaptation to increase tumour mass and intratumour hypoxia
- with increased diversity due to changing microenvironment, some cancer cells may develop new abilities that can facilitate metastasis
What is the model for transition to metastatic cancer?
Epithelial-mesenchymal transition (EMT)
When does the EMT process normally occur?
embryonic development, wound healing, and tissue repair
True or False: Metastasis is a highly efficient process
False - it is inefficient
Research in this provide much of what is known about EMT.
Carcinomas
Where does carcinomas originate from?
It originates from highly differentiated and polarized epithelial cells that form structured sheets. This is stabilized by multiple adherences to neighboring cells and to a basement membrane along the cell’s basal surface.
What prevents neoplastic cells from primary carcinoma from dissociating from ECM and metastasizing to distal site?
Retaining the epithelial like characteristics
What is needed for a phenotype to separate from the primary tumour and flourish in a potentially hostile secondary site?
A greater degree of de-differentiation
A greater degree of de-differentiation results from what factor?
Programmed transition of a still partially epithelial like carcinoma to a more undifferentiated mesenchymal-like phenotype.
During the EMT process, tumour cells develop a metastatic phenotype characterized by what factors?
suppression of adhesion molecules and reduced adherence to adjacent cells and extracellular matrix (ECM), increased local invasion, and access to the blood and lymphatic circulations.
This a major mediator of the EMT process
transforming growth factor-beta (TGF-β), which is secreted by the tumour stroma.
Thesef acilitate intravascularization of tumour cells into the circulation and tend to cluster at the leading edge of the invading cancer cells.
Protumourigenic tumour-associated macrophage (TAMs), and cancer-associated fibroblasts (CAFs)
What does Protumourigenic tumour-associated macrophage (TAMs), and cancer-associated fibroblasts (CAFs) secrete that promote digestion and remodelling of the surrounding ECM
matrix metalloproteinases
What are the functions of matrix metalloproteinases
promote digestion and remodelling of the surrounding ECM
What suppresses cytotoxic immune cells (T-cytotoxic cells and natural killer cells [NK cells])
myeloid-derived suppressor cells (MDSC).
What promotes the survival of matrix metalloproteinases
Their association with platelets promotes their survival in the circulation in addition to clotting factors that shield the cancer cells from cytotoxic immune cells
This is essential for the establishment of a metastatic site:
hematopoietic progenitor cells (HPC)
What provides a site for the influx of hematopoietic progenitor cells (HPC)
induction of fibronectin