Deck 11: Multi-Step Tumorigenesis

Question 1

A cell representing an intermediate between stem cells and their differentiated descendants is known as a

A)Precursor cell.
B)Transit-amplifying/progenitor cell.
C)Self-renewing stem cell.
D)Post-mitotic cell.
E)None of the above.

Answer 1

Transit-amplifying/progenitor cell.

Question 2

Which of the following is characteristic of field cancerization?

A)A single tumor grows from a single mutant cell.
B)Multiple tumors in an organ are separated by normal tissue.
C)Multiple tumors in an organ share the same germ-line mutation.
D)B and C.
E)A,B,and C.

Answer 2

Multiple tumors in an organ are separated by normal tissue.

Question 3

Which of the following statements is FALSE?

A)Inflammatory cells are often detected in tumor samples.
B)Cancer often arises at sites of chronic inflammation.
C)Use of NSAIDs has been associated with increased mortality from colorectal cancer.
D)The inflammatory cytokine TNF has been shown to have direct transforming properties.
E)Levels of macrophage infiltration in tumors have been negatively correlated with patient prognosis.

Answer 3

Use of NSAIDs has been associated with increased mortality from colorectal cancer.

Question 4

The rate at which mutations occur in the cells within a tumor is most likely

A)The same as in normal cells of that tissue type.
B)Less frequent than in normal cells of that tissue type.
C)More frequent than in normal cells of that tissue type.
D)Affected by genome instability within the tumor cells.
E)C and D.

Question 5

When experimental mice are treated with DMBA and TPA to induce the formation of papillomas,TPA

A)Serves as the initiating agent.
B)Serves as the promoting agent.
C)Must be administered multiple times in order for papillomas to form.
D)B and C.
E)None of the above.

Question 6

Transformation of some types of human cells has been achieved through insertion of cloned genes coding for

A)Oncogenic H-Ras alone.
B)SV40 early region and hTERT together.
C)SV40 early region and oncogenic H-Ras together.
D)hTERT and oncogenic H-Ras together.
E)Oncogenic H-Ras,SV40 early region,and hTERT together.

Question 7

Which of the following is thought to have tumor-promoting characteristics?

A)Helicobacter pylori
B)Estrogen
C)Testosterone
D)Hepatitis B virus
E)All of the above

Question 8

Patients with colon cancer often exhibit loss of heterozygosity at specific chromosomal arms.These chromosomal regions most likely include genes that act as

A)Pro-apoptotic genes.
B)Oncogenes.
C)Tumor suppressors.
D)Tumor promoters.
E)None of the above.

Question 9

Which of the following observations would support the Darwinian theory for the evolution of cancer cells?

A)Cells of the same type isolated from a tumor are all found to have multiple identical mutations.
B)Cells of the same type isolated from a tumor are found to be genetically distinct and have different types of mutations.
C)Cells isolated from a tumor are all found to have an inactivating mutation in a gene that is normally pro-apoptotic.
D)A and C.
E)None of the above.

Question 10

Which of the following is true of "complete carcinogens"?

A)They are capable of initiating tumorigenesis.
B)They promote tumorigenesis.
C)They can induce tumor formation in laboratory animals on their own without the application of additional chemicals.
D)A,B,and C
E)None of the above.

Question 11

In experiments in which rat embryo fibroblasts were transfected with suspected oncogenes,introduction of which of the following genes transformed the cells?

A)Myc alone
B)H-Ras alone
C)E1A alone
D)Both Myc and E1A together
E)Both Myc and H-Ras together

Question 12

The ability of cells to form a tumor is usually

A)The result of multiple mutations.
B)Influenced by chemicals that are nonmutagenic but act as promoters.
C)A quick process.
D)A and B.
E)None of the above.

Question 13

Which of the following types of mutations would NOT be advantageous for the survival of a cancer cell?

A)An inactivating mutation in a tumor suppressor gene
B)An inactivating mutation in an oncogene
C)An inactivating mutation in a gene that promotes apoptosis
D)Methylation of the promoter of a tumor suppressor gene
E)B and D