Carcinogenesis - 06.11.23

Question 1

Define carcinogenesis

Answer 1

The transformation of normal cells to neoplastic cells through permanent genetic alterations or mutations

Question 2

Define oncogenesis

Answer 2

Benign and malignant tumours

Question 3

What agents are known or suspected to cause tumours?

Answer 3

Carcinogenic (cancer causing), oncogenic (tumour causing) and act on DNA (are mutagenic)

Question 4

What % of cancer risk is environmental?

Answer 4

85% of cancer risk is environmental

Question 5

What chemical is known to cause bladder cancer?

Answer 5

Beta-nephthylamine

Question 6

What cancer does thorotrast cause? How?

Answer 6

Angiosarcoma of the liver.

Thorotrast (colloidal suspension of thorium, which is radioactive). Thorotrast is taken up by Kupffer cells, and has an extremely long half life and so never leaves. Irreversibly ingested by phagocytes.

Question 7

Name the 5 classes of carcinogens

Answer 7

Chemical

Viral

Ionising and non-ionising radiation

Hormones, parasites and mycotoxins

Miscellaneous

Question 8

What are pro-carcinogens and ultimate carcinogens?

Answer 8

A chemical carcinogen which requires metabolic conversion. Before it is converted it is a pro-carcinogen, then after it is an ultimate carcinogen

Question 9

Viral carcinogens causes what % of all cancer?

Answer 9

10-15%

Question 10

Most oncogenic viral infections result in cancer - true or false?

Answer 10

False - most oncogenic viral infections do NOT result in cancer

Question 11

What are the 2 groups of viral carcinogens?

Answer 11

DNA viruses and RNA viruses

Question 12

What host factors contribute to your risk of cancer?

Answer 12

Ethnicity, diet/lifestyle, constitutional factors (age, gender,etc.), premalignant lesions, transplacental exposure.