OCN Cancer Biology and Pathophysiology 1 — Questions and Answers
Question 1: Which hallmark of cancer involves the tumor's ability to grow its own blood supply?
- Sustained angiogenesis (Correct answer)
- Evading apoptosis
- Self-sufficiency in growth signals
- Limitless replicative potential
Correct answer: Sustained angiogenesis
Sustained angiogenesis is a hallmark of cancer in which tumors secrete VEGF and other factors to grow new blood vessels that supply nutrients and oxygen.
Question 2: A proto-oncogene becomes an oncogene through which process?
- Mutation, amplification, or translocation that causes gain-of-function overactivation (Correct answer)
- Deletion of the gene entirely
- Loss-of-function mutation in a tumor suppressor
- Normal aging-related methylation
Correct answer: Mutation, amplification, or translocation that causes gain-of-function overactivation
Proto-oncogenes become oncogenes when mutations, amplifications, or chromosomal translocations cause the gene product to become constitutively active.
Question 3: Which mechanism explains why cancer cells continue to divide without responding to normal growth-stop signals?
- Insensitivity to antigrowth signals (dysregulation of tumor suppressor pathways) (Correct answer)
- Increased nutrient intake
- Overproduction of hormones
- Overactivation of apoptosis
Correct answer: Insensitivity to antigrowth signals (dysregulation of tumor suppressor pathways)
Loss of tumor suppressor gene function (e.g., RB, p53) removes the normal brake on cell division, allowing cancer cells to ignore antigrowth signals.
Question 4: The Warburg effect in cancer cells refers to which metabolic phenomenon?
- Preferential use of aerobic glycolysis even in the presence of oxygen (Correct answer)
- Increased oxidative phosphorylation exclusively
- Decreased glucose uptake by cancer cells
- Preferential use of fatty acids for energy
Correct answer: Preferential use of aerobic glycolysis even in the presence of oxygen
The Warburg effect describes how cancer cells preferentially use glycolysis (even with oxygen present) to meet their high energy and biosynthetic demands.
Question 5: Metastasis occurs through which sequence of events?
- Local invasion → intravasation → circulation → extravasation → colonization (Correct answer)
- Colonization → circulation → local invasion
- Angiogenesis → extravasation → intravasation
- Apoptosis → local invasion → circulation
Correct answer: Local invasion → intravasation → circulation → extravasation → colonization
The metastatic cascade involves invasion of local tissue, entry into blood/lymphatics (intravasation), survival in circulation, exit (extravasation), and growth at a distant site.
Question 6: Which type of gene mutation is found in the germline and can be inherited by offspring?
- Germline mutation (hereditary) (Correct answer)
- Somatic mutation (acquired)
- Frameshift mutation only
- Silent mutation only
Correct answer: Germline mutation (hereditary)
Germline mutations are present in all cells of the body from birth and can be passed to children, as seen with BRCA1/2 and Lynch syndrome mutations.
OCN Cancer Biology and Pathophysiology 1
Which hallmark of cancer involves the tumor's ability to grow its own blood supply?