A24 - Carcinogenesis (chemical and physical agents)

Question 1

What is carcinogenesis?

Answer 1

It is the process where normal and healthy cells transform into cancer cells - The tumour will form.

Include something called Neoplastic transformation

Question 2

What is Neoplastic transformation ?

Answer 2

It is a process which carcinogenic chemical, oncogenic viruses or radiation change the genotype and phenotype of the cell, making the cell able to form progressively growing tumours

Neoplastic transformation has 4 steps

Question 3

Name the 4 steps of Neoplastic transformation

Answer 3

1. Initiation
2. Promotion
3. Progression
4. Malignant cell poopulation

The two first steps can be reversible !!
Proper carcinogenic agents will induce of all the steps. Incomplete carcinogenic agents, called iniciator, can trigger the initiation phase only

Question 4

What is initiation?

Answer 4

The mutation of one single cell and the proliferation ability increases

Question 5

What is the promotion?

Answer 5

The reversible effects on the cells will fasten the growth

Question 6

What is progression?

Answer 6

Initiated cell becomes malignant and we see an increases proliferation

Question 7

What is malignant cell proliferation?

Answer 7

The tumour will develop and proliferate further

Question 8

Name some natural promotional agents

Answer 8

1. Oestrogen: Causing mammary gland tumours

2. Mediators of chronic inflammation: The induce the promotion and progression in case of initiated cells

Question 9

Chemical agents

Answer 9

There are over 10 million agents, and most of them are genotoxic

They can be both direct or indirect

The carcinogenesis is dose and exposition dependent, small doses can accumulate and induce the tumour transformation and progression when they reach the dose limit

Question 10

Direct carcinogensis of chemical agents

Answer 10

The agents made the initiation phasw without the metablic transformation
Example: Chemotherapeutic agents

Question 10

Indirect carcinogensis of chemical agents

Answer 10

Metabolic transformation, moslty the Cytochromes P450

Question 11

Examples of chemical agents

Answer 11

1. Polycyclic carbohydrqates: Fossil fuels, benzoaprien (tobacco burn, cook of animal fats, smoked meat/fish inducing gastric and lung tumours)

2. Alfatoxins: Plants and microbial metabolites containing aspergillus flavus B1 (present in molds)

Question 12

Physical agents

Answer 12

1. UV-light: Animals, with white fur, no fure and extremeties without fur are most vulnerable
2. Ionising radiation: X-rays causing chromosome fragmentation