Question 1

Which of the following best describes the difference between a benign tumor and a malignant tumor?

Accepted Answer

Benign tumors remain confined to a specific area and do not invade other tissues, while malignant tumors are able to invade other tissues.

Question 2

Carcinomas account for approximately what percentage of all cancers, and from which cell type do they arise?

Accepted Answer

Carcinomas account for ~80% of all cancers and arise from epithelial cells.

Question 3

A patient is diagnosed with leukemia. Which of the following best describes the origin and behavior of leukemia cells?

Accepted Answer

Leukemia cells arise from blood and lymphatic cells and proliferate mainly in the bloodstream.

Question 4

Which Nobel Prize-winning discovery is most directly used in modern cancer diagnosis to amplify DNA from tumor samples?

Accepted Answer

Polymerase chain reaction (PCR) method

Question 5

According to the clonal evolution model of cancer, which statement is most accurate?

Accepted Answer

Cancer cells require multiple mutations to become invasive and malignant.

Question 6

A mutation in the Ras gene is found in 25-30% of human cancers. What is the effect of a hyperactive Ras protein on cell behavior?

Accepted Answer

It causes uncontrolled cell proliferation even in the absence of extracellular signals.

Question 7

Which equation best describes exponential tumor cell growth, where $$N is $$the number of cells after $$n$$ doublings, and $$N_0 is $$the initial number of cells?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 8

Based on the graph showing tumor cell population doublings, at approximately how many doublings does a tumor become first visible on an x-ray?

Accepted Answer

At 27 doublings

Question 9

Which of the following best explains why cancer is considered a disease of old age?

Accepted Answer

Cancer prevalence increases with age due to the accumulation of somatic mutations over time.

Question 10

A patient has a tumor that is confined to a specific area and does not invade other tissues. Which term best describes this tumor?

Accepted Answer

Benign tumor

Question 11

Which of the following is a common misconception about cancer cell proliferation?

Accepted Answer

Cancer cells require extracellular signals to proliferate.

Question 12

Which real-world factor is most strongly correlated with the onset of lung cancer, as shown in the provided graph?

Accepted Answer

Cigarette smoking

Question 13

If a tumor is first palpable at $$10^9$$ cells and first visible on x-ray at $$10^8$$ cells, how many doublings does it take to go from x-ray visible to palpable?

Accepted Answer

4 doublings

Question 14

Which of the following best describes the process of clonal evolution in cancer?

Accepted Answer

Tumor progression involves the accumulation of multiple mutations, leading to increasingly aggressive cell behavior.

Question 15

Which type of cancer arises from cells of supporting tissues such as bone, cartilage, fat, connective tissue, and muscle?

Accepted Answer

Sarcoma

Question 16

A cell acquires a mutation that allows it to proliferate uncontrollably. According to the multi-step model of cancer, what must happen next for the cell to become invasive?

Accepted Answer

The cell must acquire additional mutations that enable invasive cell proliferation.

Question 17

Which Nobel Prize-winning discovery is most relevant to studying circadian rhythm in cancer cells?

Accepted Answer

Molecular mechanisms controlling the circadian rhythm

Question 18

Which of the following is NOT a characteristic of cancer cells?

Accepted Answer

Dependence on extracellular signals for growth

Question 19

If the prevalence of cancer increases with age, which equation best models the relationship between cancer prevalence ($$P) $$and age ($$a$$), assuming a simple exponential relationship?

Accepted Answer

$$P = k 	imes e$$^{ma}$$

Question 20

Which of the following best explains why most cancers derive from a single abnormal cell?

Accepted Answer

Somatic mutations in a single cell can lead to uncontrolled proliferation, resulting in a tumor.

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