Neoplasia

Question 1

Formation of neoplasm

Answer 1

Made of tumour cells and stroma.
Stroma is inflammatory cells, fibroblasts, ECM, new blood vessels
Cross talk between EXM and tumour cells may promote tumour cell division, maintenance, migration and development of new blood vessels.
VEGF (vascular endothelial growth factor) from stroma promotes angiogenesis.
Cancer is usually made up of one cell type. Eg. Squamous cells.
Monoclonal theory; tumour cells arise from a single cell.

Question 2

Benign tumour

Answer 2

Not normally life threatening.
Slow and steady growth rate.
Often have a capsule formed by layers of connective tissue encasing the tumour.
Well differentiated- looks and acts similar to normal cells.
Non- invasive but grow expansively do can compress surrounding tissue

Question 3

Malignant tumours

Answer 3

Often life threatening 
Rapid growth rate
Seldom have a capsule 
Can be well differentiation or poorly differentiated. Poorly does not look or act similar to normal cells, hence does not behave normally. 
Grow invasively.

Question 4

Carcinogens

Answer 4

Agents which increase the risk of developing cancer.
Higher the dose, greater the risk of developing cancer.
Some carcinogens cause cancer where they contact the cells (direct acting carcinogens), but most carcinogens cause cancer after they’re metabolised (procarcinogen). Often these are in an inactive state and will produce and active compound in another area of the body.
- nitrosamines- formed from nitrates and amines, can be found in vegetables, pesticides, cigarettes etc.
- biological agents- bacteria, viruses etc
- physical agents- x-ray, UV radiation (depends on number of hits in a cell)

Question 5

Skin cancer

Answer 5

Basal cell carcinomas are found on area of skin exposed to sunlight. Some BCC’s contain melanin and resemble melanomas.
Squamous cell carcinomas found on areas of the skin commonly exposed to sunlight.
Melanoma- only needs to invert into the skin a little bit to spread to other tissues.

Question 6

Tumour development

Answer 6

Progression of changes to cells that may be seen in the development of cancer. 
- normal hit by carcinogen 
- hyperplasia
- atypical hyperplasia
- dysplasia
- Metaplasia
- benign tumour 
- malignant tumour in site
- invasive tumour 
- metastatic tumour 
- development is a multi step process 
Initiation by carcinogen- mutation occurs to cell 
Promotion (cell division) is effected by non- carcinogenic agents- promoting agents induce cell replication

Question 7

Neoplasia

Answer 7

The formation of new tissue growth- benign or malignant tumour growth, irreversible injury due to stress etc such as necrosis or neoplasia.
Involves constant replication of cells, and cells become abnormal.

Question 8

Local invasion

Answer 8

Tumour cells Aquire ability to break away from their neighbours.
Able to move away from the main growth because there are fewer adhesion molecules.
Tumour cells cause resident fibroblasts to secrete enzymes which will destroy surround tissue, enabling the tumour cells to spread further.
Cancer cells invade through blood vessel or lymphatic vessel walls.
If the cancer cell does this and enters another body cavity, it is the secondary growth.

Question 9

Local invasion

Answer 9

Tumour cells Aquire ability to break away from their neighbours.
Able to move away from the main growth because there are fewer adhesion molecules.
Tumour cells cause resident fibroblasts to secrete enzymes which will destroy surround tissue, enabling the tumour cells to spread further.
Cancer cells invade through blood vessel or lymphatic vessel walls.
If the cancer cell does this and enters another body cavity, it is the secondary growth.