Lecture 3 Flashcards
Lecture 3:
What are Tumour Suppressor Genes?
They suppress oncogenes & inhibit excessive cell proliferation (division) thus they prevent rapid cancer cell division & try to control this
Lecture 3:
What happens when there is a mutation in tumour suppressor genes?
T-s genes lose their function & therefore nothing is able to suppress oncogenes
Lecture 3:
What is the inactivation of tumour-suppressor genes typically associated with?
inactivation of tumour-suppressor genes typically associated with inherited cancers
- can also be sporadic cancers (by chance) eg; Wild;s Tumour
Lecture 3:
Where does Wilms’ Tumour originate & what is another name for it?
Type of kidney cancer called neuroblastoma that originated in cells of kidney & is the most common type of renal cancer
Lecture 3:
What is Wilms’ Tumour caused by & is it inherited or sporadic?
Caused by genetic mutations in kidney cells in utero (embryonic tumour) & most cases are sporadic & not inherited (2% inherited)
Lecture 3:
What age group is affected by Wilms’ Tumour?
Occurs in children up to 10 years with mean age of 43-48 months (3-4 years)
- accounts for 6% all childhood cancers
Lecture 3:
What percent of Wilms’ Tumours are single kidney?
- explain why
- what if double?
90-95% of cases are in a single kidney (only one cell that mutates and mutations remain in original kidney)
- if bilateral (in both kidneys) than typically an inherited type
Lecture 3:
What are 4 gene types associated with Wilms’ Tumour?
1.) TP53 - classic tumour suppressor gene
2.) CTNNB1 - classic oncogene
3.) WTX - tumour suppressor gene
4.) WT1 - similar to tumour suppressor gene
Lecture 3:
What are 5 key properties of tumour cells?
1.) proliferate (divide) indefinitely
2.) less cell adhesion (sticking together)
3.) Ability to continue growing despite crowding (normal cells stop growing due to lack of space but cancerous cells don’t)
4.) Reduces apoptosis (cell death)
5.) Many other properties that make them different from normal cells
Lecture 3:
What is Metastasis?
Migration of cancer cells from the original tumour site through the blood & lymph to other tissues
Lecture 3:
What is metastasis a major cause of and what would happen if this wasn’t a thing?
Metastasis is a major cause of cancer deaths and without it, many cancers would be harmless as cancer cells wouldn’t spread around the body
Lecture 3:
What are 5 conditions that must be met for metastases to be successful?
1.) Angiogenesis
2.) Motility
3.) Alterations in cell adhesion
4.) Secretion of proteolytic enzymes
5.) Ability to escape immune surveillance
Lecture 3:
What is Angiogenesis?
The development of new blood vessels to support growing tumours by providing blood supply
Lecture 3:
Why is Angiogenesis important for Metastases?
Blood supply is needed for primary tumour to grow
Lecture 3:
What is Angiogenesis’s role in metastases?
New blood vessels provide an escape route for metastatic cells to get into blood stream & travel to other parts of body
- degree of angiogenesis in primary tumour determines likelihood of metastases
Lecture 3:
What is Motility?
The ability for a cell to move under its own power
Lecture 3:
Why is Motility needed for metastases?
Needed for a tumour cell to leave the primary tumour & circulate throughout the blood or lymphatic system
*if this doesn’t happen, no metastases
Lecture 3:
What is Cell Adhesion & it’s importance to metastases?
Cancer cells must be able to adhere/stick to the extracellular matrix and NOT to other cells
*have to be able to escape without sticking until they reach desired location
Lecture 3:
What are Proteolytic Enzymes?
Enzymes secreted by cancer cells in order to break down barriers to get into circulation & form new tumour beds
Lecture 3:
What are 3 types of barriers that are broken down by Proteolytic enzymes?
1.) Basement membranes
2.) Extracellular matrix
3.) Endothelial barrier
Lecture 3:
Why is it critical for cancer cells to have the ability to escape immune surveillance for metastasizing?
Tumour cells have to be able to hide from immune system and their enzymes such as;
- cytoxic T lymphocytes
- Activated macrophages
- Natural killer cells
Lecture 3:
What are the 5 components of the Metastatic Cascade?
1.) Primary Tumour Forms
2.) Angiogenesis & Invasion
3.) Survival in Circulation
4.) Tumour Cells Arrest in Capillary Bed of Organ
5.) Establishment of Secondary Tumour
