PHM 480D EXAM 4 COMPLETE QUESTIONS WITH 100%
VERIFIED ANSWERS
1. What is the primary function of tumor suppressor genes like PTEN?
A. Stimulate angiogenesis
B. Promote uncontrolled proliferation
C. Regulate cell cycle checkpoints and prevent unregulated growth
D. Induce chromosomal translocations
Correct Answer: C
Explanation: Tumor suppressor genes such as PTEN normally function to
regulate cell cycle checkpoints and prevent unregulated growth. PTEN
specifically acts as a phosphatase that negatively regulates the
PI3K/AKT signaling pathway, promoting apoptosis and inhibiting cell
proliferation. Loss of function leads to unchecked growth and survival.
2. Which receptor is frequently overexpressed in breast cancer?
A. EGFR
B. VEGFR
C. HER2
D. IGF-IR
Correct Answer: C
Explanation: HER2 (human epidermal growth factor receptor 2) is
overexpressed in approximately 15-20% of breast cancers. This
overexpression is associated with aggressive tumor behavior and poorer
,prognosis. HER2-targeted therapies such as trastuzumab have
significantly improved outcomes for HER2-positive breast cancer
patients.
3. Which growth factor primarily promotes angiogenesis in tumors?
A. EGF
B. FGF
C. VEGF
D. IGF-1
Correct Answer: C
Explanation: Vascular endothelial growth factor (VEGF) is the primary
growth factor responsible for promoting angiogenesis in tumors. It
stimulates endothelial cell proliferation, migration, and tube formation,
leading to new blood vessel growth that supplies oxygen and nutrients
to the growing tumor.
4. Which gene mutation leads to unregulated tyrosine kinase activity
in Chronic Myelogenous Leukemia (CML)?
A. p53
B. BCR-ABL
C. Ras
D. MYC
Correct Answer: B
Explanation: The BCR-ABL fusion gene results from the Philadelphia
chromosome translocation t(9;22). This fusion creates a constitutively
,active tyrosine kinase that drives uncontrolled proliferation of myeloid
cells in CML. Tyrosine kinase inhibitors like imatinib target this aberrant
kinase activity.
5. Loss of function in ______ proteins leads to unregulated cell
proliferation and survival.
A. Oncogene
B. Tumor suppressor
C. Kinase
D. Growth factor
Correct Answer: B
Explanation: Tumor suppressor proteins normally act as "brakes" on cell
proliferation. When their function is lost through mutation or epigenetic
silencing, cells can proliferate uncontrollably and evade apoptosis. This
loss of function is a hallmark of cancer development.
6. The process by which tumors stimulate blood vessel formation is
called ______.
A. Metastasis
B. Angiogenesis
C. Vascularization
D. Neoplasm
Correct Answer: B
Explanation: Angiogenesis is the physiological process by which new
blood vessels form from pre-existing vessels. Tumors stimulate this
, process to secure adequate blood supply for continued growth and
expansion. This process is mediated by pro-angiogenic factors such as
VEGF.
7. True/False: Caspases are responsible for initiating the cell cycle.
A. True
B. False
Correct Answer: B
Explanation: Caspases are not responsible for initiating the cell cycle.
Instead, they are a family of protease enzymes that play essential roles
in programmed cell death (apoptosis). Caspases execute apoptosis by
cleaving specific cellular substrates, leading to the characteristic
morphological changes of cell death.
8. True/False: Oncogenes arise from mutations or overexpression of
proto-oncogenes.
A. True
B. False
Correct Answer: A
Explanation: Proto-oncogenes are normal genes that promote cell
growth and division. When mutated or overexpressed, they become
oncogenes that can drive cancer development. This activation can occur
through point mutations, gene amplification, or chromosomal
translocations that lead to gain-of-function changes.
VERIFIED ANSWERS
1. What is the primary function of tumor suppressor genes like PTEN?
A. Stimulate angiogenesis
B. Promote uncontrolled proliferation
C. Regulate cell cycle checkpoints and prevent unregulated growth
D. Induce chromosomal translocations
Correct Answer: C
Explanation: Tumor suppressor genes such as PTEN normally function to
regulate cell cycle checkpoints and prevent unregulated growth. PTEN
specifically acts as a phosphatase that negatively regulates the
PI3K/AKT signaling pathway, promoting apoptosis and inhibiting cell
proliferation. Loss of function leads to unchecked growth and survival.
2. Which receptor is frequently overexpressed in breast cancer?
A. EGFR
B. VEGFR
C. HER2
D. IGF-IR
Correct Answer: C
Explanation: HER2 (human epidermal growth factor receptor 2) is
overexpressed in approximately 15-20% of breast cancers. This
overexpression is associated with aggressive tumor behavior and poorer
,prognosis. HER2-targeted therapies such as trastuzumab have
significantly improved outcomes for HER2-positive breast cancer
patients.
3. Which growth factor primarily promotes angiogenesis in tumors?
A. EGF
B. FGF
C. VEGF
D. IGF-1
Correct Answer: C
Explanation: Vascular endothelial growth factor (VEGF) is the primary
growth factor responsible for promoting angiogenesis in tumors. It
stimulates endothelial cell proliferation, migration, and tube formation,
leading to new blood vessel growth that supplies oxygen and nutrients
to the growing tumor.
4. Which gene mutation leads to unregulated tyrosine kinase activity
in Chronic Myelogenous Leukemia (CML)?
A. p53
B. BCR-ABL
C. Ras
D. MYC
Correct Answer: B
Explanation: The BCR-ABL fusion gene results from the Philadelphia
chromosome translocation t(9;22). This fusion creates a constitutively
,active tyrosine kinase that drives uncontrolled proliferation of myeloid
cells in CML. Tyrosine kinase inhibitors like imatinib target this aberrant
kinase activity.
5. Loss of function in ______ proteins leads to unregulated cell
proliferation and survival.
A. Oncogene
B. Tumor suppressor
C. Kinase
D. Growth factor
Correct Answer: B
Explanation: Tumor suppressor proteins normally act as "brakes" on cell
proliferation. When their function is lost through mutation or epigenetic
silencing, cells can proliferate uncontrollably and evade apoptosis. This
loss of function is a hallmark of cancer development.
6. The process by which tumors stimulate blood vessel formation is
called ______.
A. Metastasis
B. Angiogenesis
C. Vascularization
D. Neoplasm
Correct Answer: B
Explanation: Angiogenesis is the physiological process by which new
blood vessels form from pre-existing vessels. Tumors stimulate this
, process to secure adequate blood supply for continued growth and
expansion. This process is mediated by pro-angiogenic factors such as
VEGF.
7. True/False: Caspases are responsible for initiating the cell cycle.
A. True
B. False
Correct Answer: B
Explanation: Caspases are not responsible for initiating the cell cycle.
Instead, they are a family of protease enzymes that play essential roles
in programmed cell death (apoptosis). Caspases execute apoptosis by
cleaving specific cellular substrates, leading to the characteristic
morphological changes of cell death.
8. True/False: Oncogenes arise from mutations or overexpression of
proto-oncogenes.
A. True
B. False
Correct Answer: A
Explanation: Proto-oncogenes are normal genes that promote cell
growth and division. When mutated or overexpressed, they become
oncogenes that can drive cancer development. This activation can occur
through point mutations, gene amplification, or chromosomal
translocations that lead to gain-of-function changes.
