Lecture 29 - Neo 3

Question 1

What is an example of common neoplasms that are found in veterinary practice?

Answer 1

Adenoma, Lipoma, Histiocytoma

Question 2

What are the three main factors that cause neoplasia?

Answer 2

1. Age
2. Inherited factors
3. Environmental factors

Question 3

In general terms what sequence of genetically irreversible initiators and promoter (non-genetic, reversible) factors are needed to form a neoplasms?

Answer 3

To form a neoplasm you need a initiator (genetic irreversible) and then a series of promoters (non-genetic, reversible)

Question 4

How do the direct-acting carcinogens act?

Answer 4

causes damage in the same state it was introduced into the body in

Question 5

How do the indirect pro-carcinogens act?

Answer 5

have to be metabolised to something else before they can become carcinogenic

Question 6

How do the promotors (co-carcinogens) act?

Answer 6

they promote the growth of cells (they are not carcinogens by themselves)

Question 7

What is an example of a direct acting chemical carcinogen?

Answer 7

dimethyl sulfate

Question 8

What is an example of a chemical pro-carcinogen?

Answer 8

petroleum

Question 9

What is an example of a chemical carcinogen promoter?

Answer 9

artificial sweetener

Question 10

What is an example of a carcinogenic DNA virus?

Answer 10

Human papilloma virus

Question 11

What is the mechanism of action of a papillomavirus?

Answer 11

It stops p53 from being generated

Question 12

What are the three genes is slowly transforming retroviruses and what is the function of them?

Answer 12

gag = viral capsid
pol = reverse transcriptase 
env = envelope proteins

Long-term repeats (LTR) contain viral promoters and enhancers. The expression of cellular gene is altered by insertion of LTRs “insertional mutagenesis”

Question 13

How do acutely transforming retroviruses occur?

Answer 13

Partial deletion of permits the inclusion of v-onc. But they are often replication-defective and hence require helper virus help

Question 14

How does chronic inflammation increase the risk of cancer?

Answer 14

Repair and regeneration - involves cytokines, growth factors and stem cells.

Chemical mediators & ROS are genotoxic causing mutations

Question 15

Why do some tumours regress spontaneously?

Answer 15

Due to the inflammation of the neoplasm by cytotoxic CD8+ inducing apoptosis of the neoplastic cell