Etiology and Pathogenesis of Cancer

Question 1

Name three factors that affect the frequency of a cancer in a given population.

Answer 1

no answer

Question 2

Identify the neoplasm for which vinyl chloride most greatly increases risk.

Answer 2

no answer

Question 3

Define “initiator” and “promoter” and distinguish their roles in carcinogenesis.

Answer 3

Initiator: Mutagenic (irreversible)
Promoter: Not mutagenic (promotion is reversible)
Two stage model of carcinogenesis

Question 4

Explain the “two hit” hypothesis of carcinogenesis.

Answer 4

• Proto-oncogene can be activated in the genome
• Successive of clonal expansions
• Carcinogenesis alter exiting genes and chromosome structure

Question 5

Explain the hypothesis that underlies the Ames Bacterial Assay for mutagenesis.

Answer 5

• Pro-carcinogens: mutagenic only if metabolized to an active form
• Ultimate carcinogenic: mutagenic without

Question 6

Cite three diseases that highlight the role of defective DNA repair in carcinogenesis.

Answer 6

• Xeroderma pigmentosum

* Hereditary nonpolyposus Colon Cancer

Question 7

List five factors that modify the risk of an at-risk individual developing cancer.

Answer 7

• Genome instability
• Tumor-promoting inflammation
• Permissive sues from altered stromal microenvironment

Question 8

Discuss how infectious agents such as HPV and RSV lead to cancer production

Answer 8

• Viruses initiate & maintain transformed phenotype of host cells
• RSV
o RSV gene (src gene) is required to Initiate & maintain transformed phenotype
o Src gene = first known proto-oncogene
o Insertional mutagenesis by slowly tumorigenic retroviruses