Q: Which equation best describes the probability of a cell acquiring two independent mutations in the same gene, as discussed in the context of Knudson’s two-hit model?

$$P = (1 \times 10$$^{-5}$$) \times (1 \times 10$$^{-5}$$) = 1 \times 10$$^{-10}$$

Question 1

Which of the following is a hallmark of cancer cells, as illustrated in the first image, that allows them to grow beyond a small size?

Accepted Answer

Sustained angiogenesis

Question 2

A child presents with tumors in both eyes, as shown in the second image. According to Knudson's two-hit hypothesis, what is the most likely genetic explanation for this bilateral retinoblastoma?

Accepted Answer

The child inherited one defective copy of the RB gene and acquired a second somatic mutation.

Question 3

Based on the third image, which cancer type is most strongly associated with p53 mutations in developed countries?

Accepted Answer

Lung cancer

Question 4

Which step in the metastatic cascade, as shown in the fourth image, is most responsible for the formation of secondary tumors in distant organs?

Accepted Answer

Macrometastatic growth

Question 5

A patient’s lung X-ray (fifth image) shows a large mass. Which of the following statements about lung cancer is correct based on the study materials?

Accepted Answer

Lung cancer is strongly linked to tobacco use, which is a major mutagen.

Question 6

According to the sixth image, which cancer type is the leading cause of cancer death in females in the US?

Accepted Answer

Lung & bronchus

Question 7

The seventh image shows trends in cancer death rates. Which cancer type has seen the most significant decrease in age-adjusted death rates since 1930?

Accepted Answer

Stomach

Question 8

Based on the eighth image, which cancer type has the highest 5-year relative survival rate for all races and ethnicities in 2015-2021?

Accepted Answer

Prostate

Question 9

The ninth image compares normal cells and cancer cells. Which property of cancer cells is illustrated by their ability to grow beyond the boundaries of normal tissue?

Accepted Answer

Loss of contact inhibition

Question 10

Which equation best describes the probability of a cell acquiring two independent mutations in the same gene, as discussed in the context of Knudson’s two-hit model?

Accepted Answer

$$P = (1 	imes 10$$^{-5}$$) 	imes (1 	imes 10$$^{-5}$$) = 1 	imes 10$$^{-10}$$

Question 11

Which gene is most commonly mutated in human cancers, leading to loss of DNA damage checkpoints and increased mutation accumulation?

Accepted Answer

p53

Question 12

A missense mutation in the Ras gene (G12V) causes Ras to remain active. What is the consequence of this mutation for cell division?

Accepted Answer

Cells divide uncontrollably, even without growth factor signals.

Question 13

Which of the following statements about oncogenes is correct?

Accepted Answer

Oncogenes are mutated versions of proto-oncogenes and act in a dominant manner.

Question 14

Which type of gene mutation is most likely to result in a loss of cell cycle checkpoints, allowing cells with damaged DNA to continue dividing?

Accepted Answer

Tumor suppressor gene loss-of-function mutation

Question 15

Individuals with xeroderma pigmentosum (XP) have a defect in which DNA repair system, leading to a 1000X increased mutation rate?

Accepted Answer

Nucleotide excision repair

Question 16

Which environmental factor is most strongly implicated in the development of skin cancer?

Accepted Answer

UV radiation

Question 17

Germline mutations in BRCA1 and BRCA2 genes predispose individuals to which types of cancer?

Accepted Answer

Breast and ovarian cancer

Question 18

Which property of cancer cells allows them to grow indefinitely in tissue culture, as seen in immortalized cell lines like HeLa?

Accepted Answer

Activation of telomerase

Question 19

Which equation describes the probability of developing retinoblastoma in both eyes if a child is born with a germline mutation in one RB gene copy and the somatic mutation rate is $$1 	imes 10$$^{-5}$$?

Accepted Answer

$$P = 1 	imes 10$$^{-5}$$

Question 20

Which of the following best explains why cancer is considered a rare event, despite millions of cells in the body?

Accepted Answer

Cancer requires the accumulation of mutations in multiple key genes within the same cell.

Genetics of Cancer: Mechanisms, Mutations, and Cellular Pathways 20

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