Question 1

Which of the following best describes the two fundamental properties shared by all cancer cells?

Accepted Answer

Unregulated cell proliferation and metastasis

Question 2

A mutation in the p53 gene is most likely to result in which of the following cellular outcomes?

Accepted Answer

Failure to arrest the cell cycle and inability to initiate apoptosis

Question 3

Which equation best represents the probability of developing invasive cancer in a population, given the incidence rate $$i$$ and population size $$N$$?

Accepted Answer

$$P = 1 - (1 - i)^N$$

Question 4

Which gene is most commonly mutated in human cancers and acts as a transcription factor regulating over 50 genes?

Accepted Answer

p53

Question 5

A dominant mutation that causes unregulated cell growth and produces a protein product is most likely found in which type of gene?

Accepted Answer

Oncogene

Question 6

Which of the following best describes the role of stability genes (caretaker genes) in cancer development?

Accepted Answer

They repair DNA mistakes and maintain chromosomal integrity

Question 7

Which of the following environmental factors is most likely to cause mutations in proto-oncogenes or tumor suppressor genes?

Accepted Answer

Carcinogens such as chemicals, radiation, and viruses

Question 8

In the multistep model of colon cancer development, which sequence of genetic alterations is most accurate?

Accepted Answer

APC mutation → ras mutation → DCC loss → p53 loss

Question 9

Which checkpoint in the cell cycle is responsible for monitoring spindle formation and attachment to kinetochores?

Accepted Answer

M checkpoint

Question 10

If a cell has a loss-of-function mutation in RB1, which phase of the cell cycle is most likely to be affected?

Accepted Answer

G1/S transition

Question 11

Which of the following best explains why most inherited cancer-susceptibility genes are not sufficient in themselves to trigger cancer development?

Accepted Answer

Multiple mutations are required for full cancer phenotype expression

Question 12

Which of the following is a plausible consequence of epigenetic changes such as DNA methylation and histone acetylation in cancer cells?

Accepted Answer

Transcriptional silencing of DNA repair genes like MLH1 and BRCA1

Question 13

Which equation best describes the relationship between the number of mutations ($$m) $$and the probability of cancer development ($$P$$), assuming each mutation is independent and necessary?

Accepted Answer

$$P = 1 - (1 - p)^m$$

Question 14

Which of the following statements about proto-oncogenes is correct?

Accepted Answer

Only one allele needs to mutate or be mis-expressed to contribute to cancer

Question 15

A patient with a family history of hereditary cancer is found to have a mutation in a DNA repair gene. Which type of gene is most likely affected?

Accepted Answer

Stability gene (caretaker gene)

Question 16

Which of the following best describes the effect of a passenger mutation in a cancer cell?

Accepted Answer

It has no direct contribution to the cancer phenotype

Question 17

Which of the following scenarios illustrates the concept of 'contact inhibition'?

Accepted Answer

Normal cells stop dividing when they touch neighboring cells

Question 18

Which of the following best explains why cancer is considered an age-related disease?

Accepted Answer

Multiple mutations accumulate over time, increasing cancer risk with age

Question 19

Which of the following is a real-world example of a carcinogen that can cause mutations leading to cancer?

Accepted Answer

Tobacco smoke

Question 20

Which of the following best describes the function of the G1/S checkpoint in the cell cycle?

Accepted Answer

Monitors cell size and DNA integrity before DNA replication

Cancer Genetics: Mechanisms, Genes, and Environmental Factors

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