Two-stage Carinogenesis: Initiation And Promotion

Question 1

Who carries out the two-stage cacinogenesis experiments?

Answer 1

Isaac Berenblum

Question 2

What substance did Berenblum use for his experiments?

Answer 2

Purified cacinogenic elements from coal tar

Question 3

What is the carcinogen called?

Answer 3

The initiator

Question 4

What happens when the initiator in repeatedly applied to the skin over a long period of time?

Answer 4

A carcinoma developes (Yamagiwa)

Question 5

What is a promoter? Which did Berenblum use in his experiments

Answer 5

It is an irritant which causes an inflammatory response. On its own it does not cause cancer

Berenblum used croton oil

Question 6

What occurs in skin exposed to an initiator just once (or very few times) then repeatedly treated with a promoter?

Answer 6

The result is a benign tumour, a papilloma

Question 7

At the papilloma stage, what happens if promoter treatment is halted?

Answer 7

The papilloma regresses and disappears

Question 8

At the papilloma stage, what happens if you continue to treat the local area with promoter?

Answer 8

It continues to develope and reaches a stage where it will not regress even if promoter treatment is halted.
If it is further treated with promotor it will become a carcinoma

Question 9

Describe how one can develope a papilloma to a carcinoma

Answer 9

Continue treatment with promoter (long term)

Or expose the papilloma to the original initiator (short term or even one application)

Question 10

We must no only have to understand and control the _________ but we have to understand how the _______ works and how they can contribute to human cancer

Answer 10

Initiator (carcinogen) ; promoter