OCN Cancer Biology and Pathophysiology

Question 1

Which hallmark of cancer involves the tumor's ability to grow its own blood supply?

Accepted Answer

Sustained angiogenesis

Answer

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?

Accepted Answer

Mutation, amplification, or translocation that causes gain-of-function overactivation

Answer

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?

Accepted Answer

Insensitivity to antigrowth signals (dysregulation of tumor suppressor pathways)

Answer

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?

Accepted Answer

Preferential use of aerobic glycolysis even in the presence of oxygen

Answer

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?

Accepted Answer

Local invasion → intravasation → circulation → extravasation → colonization

Answer

The metastatic cascade involves invasion of local tissue, entry into blood/lymphatics (intravasation), survival in circulation, exit (extravasation), and growth at a distant site.

OCN Exam Practice Test

OCN Exam Practice Test

OCN Cancer Biology and Pathophysiology