Question 1

Which of the following best explains why cancer is considered a genetic disease of somatic cells?

Accepted Answer

Cancer is caused by mutations in the DNA of somatic cells, leading to uncontrolled cell growth.

Question 2

A patient is diagnosed with chronic myeloid leukemia (CML). Which chromosomal abnormality is most likely present in their cells?

Accepted Answer

A reciprocal translocation between chromosomes 9 and 22, forming the Philadelphia chromosome.

Question 3

Which of the following best describes the difference between proto-oncogenes and tumor suppressor genes?

Accepted Answer

Proto-oncogenes promote cell division, while tumor suppressor genes inhibit it.

Question 4

A gain-of-function mutation in a proto-oncogene results in which of the following?

Accepted Answer

The gene becomes an oncogene and promotes uncontrolled cell division.

Question 5

Which of the following is a hallmark of cancer cells, as described by Hanahan and Weinberg?

Accepted Answer

Evading apoptosis

Question 6

A woman inherits one mutant allele of the BRCA1 gene. What must occur for her to develop cancer related to this gene?

Accepted Answer

A second, somatic mutation must occur in the other BRCA1 allele (the 'two-hit' hypothesis).

Question 7

Which of the following types of mutations is NOT commonly associated with cancer development?

Accepted Answer

Silent mutations that do not alter the amino acid sequence

Question 8

Refer to the cell cycle diagram. Which checkpoint is most likely to prevent a cell with damaged DNA from entering mitosis?

Accepted Answer

The G2/M checkpoint

Question 9

A patient is treated with Gleevec for chronic myeloid leukemia. What is the mechanism of action of this drug?

Accepted Answer

It inhibits the BCR-ABL kinase, blocking growth and survival signals in cancer cells.

Question 10

Which of the following best explains why cancer is not considered a single disease?

Accepted Answer

Cancers arise from different cell types and involve mutations in different sets of genes.

Question 11

A karyotype from a cancer cell shows multiple chromosomal abnormalities. What does this suggest about the genome of cancer cells?

Accepted Answer

Cancer cells often have genome instability, leading to structural chromosomal changes.

Question 12

Which of the following scenarios best illustrates the 'multi-hit' model of cancer development?

Accepted Answer

A colon cell accumulates mutations in APC, Ras, DCC, and p53 genes over time, eventually becoming cancerous.

Question 13

Which of the following is a real-world example of a cancer caused by a chromosomal translocation that creates a fusion gene?

Accepted Answer

Chronic myeloid leukemia caused by the BCR-ABL fusion gene

Question 14

Which of the following best describes the role of tumor suppressor genes in the cell cycle?

Accepted Answer

They act as brakes, blocking cell cycle progression or promoting DNA repair.

Question 15

A patient with Burkitt's lymphoma has a translocation between chromosomes 8 and 14. What is the consequence of this translocation?

Accepted Answer

Overexpression of the c-MYC gene, leading to increased cell proliferation.

Question 16

Which of the following best explains why most chemotherapies have significant side effects?

Accepted Answer

They target all rapidly dividing cells, not just cancer cells.

Question 17

Which of the following equations best represents the probability $$P of a $$cell becoming cancerous if $$n$$ independent mutations are required and the probability of each mutation is $$p$$?

Accepted Answer

$$P = p^n$$

Question 18

Which of the following is a key difference between inherited (familial) and sporadic cancers?

Accepted Answer

Inherited cancers involve a germline mutation present in all cells, while sporadic cancers arise from somatic mutations.

Question 19

Which of the following best describes the process of metastasis?

Accepted Answer

Cancer cells invade surrounding tissues and spread to distant sites via the circulatory system.

Question 20

Which of the following is a real-world example of a targeted cancer therapy and its molecular target?

Accepted Answer

Herceptin targets the HER2 growth factor receptor in breast cancer.

Lecture 13: Genetic Basis and Molecular Mechanisms of Cancer

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