ROBBINS BASIC PATHOLOGY
10TH EDITION
AUTHOR(S)VINAY KUMAR; ABUL K.
ABBAS; JON C. ASTER
TEST BANK
1
Reference
Ch. 1 — The Cell as a Unit of Health and Disease — The
Genome
Question Stem
A 42-year-old patient presents with a family history of early-
onset colon cancer. Genetic testing returns a missense mutation
in a DNA mismatch repair gene. Which cellular consequence
best explains how this mutation increases cancer risk?
Options
A. Increased production of reactive oxygen species leading to
DNA strand breaks
B. Loss of correction of replication errors causing accumulation
,of point mutations and microsatellite instability
C. Failure of non-homologous end joining, causing chromosome
translocations
D. Enhanced base-excision repair causing hypermutation of
repetitive sequences
Correct Answer
B
Rationales
• Correct (B): Mismatch repair proteins correct replication
errors; loss leads to unrepaired base–base mismatches and
insertion/deletion loops, producing point mutations and
microsatellite instability, which drive tumorigenesis.
• Incorrect (A): Reactive oxygen species cause oxidative DNA
damage but are not the primary consequence of defective
mismatch repair.
• Incorrect (C): Non-homologous end joining repairs double-
strand breaks; mismatch repair defects do not primarily
cause DSB repair failure or translocations.
• Incorrect (D): Base-excision repair corrects small base
lesions; mismatch repair deficiency does not enhance
base-excision repair or produce hypermutation of repeats.
Teaching Point
Mismatch repair failure → replication errors persist → point
mutations and microsatellite instability.
,Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
2
Reference
Ch. 1 — The Cell as a Unit of Health and Disease — The
Genome
Question Stem
A newborn screening shows a homozygous nonsense mutation
in a gene required for nucleotide excision repair (NER). Which
environmental exposure should clinicians advise the family to
strictly avoid to reduce cancer risk?
Options
A. Ionizing radiation (X-rays)
B. Ultraviolet (UV) sunlight exposure
C. High-fat diet
D. Tobacco smoke
Correct Answer
B
Rationales
• Correct (B): NER removes UV-induced bulky pyrimidine
dimers; defective NER makes cells highly sensitive to UV,
markedly increasing skin cancer risk.
, • Incorrect (A): Ionizing radiation primarily causes double-
strand breaks; while harmful, NER deficiency specifically
predisposes to UV-induced damage.
• Incorrect (C): Diet influences cancer risk indirectly but is
not the primary risk in NER deficiency.
• Incorrect (D): Tobacco causes DNA adducts repaired
mainly by NER and other pathways, but UV avoidance is
the most critical immediate protection for NER defects.
Teaching Point
NER deficiency → extreme sensitivity to UV-induced DNA
lesions; avoid sun exposure.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
3
Reference
Ch. 1 — The Cell as a Unit of Health and Disease — Cellular
Housekeeping
Question Stem
A patient with a neurodegenerative disorder shows
accumulation of ubiquitinated protein aggregates in neurons.
Which cellular pathway dysfunction most likely explains this
finding?
10TH EDITION
AUTHOR(S)VINAY KUMAR; ABUL K.
ABBAS; JON C. ASTER
TEST BANK
1
Reference
Ch. 1 — The Cell as a Unit of Health and Disease — The
Genome
Question Stem
A 42-year-old patient presents with a family history of early-
onset colon cancer. Genetic testing returns a missense mutation
in a DNA mismatch repair gene. Which cellular consequence
best explains how this mutation increases cancer risk?
Options
A. Increased production of reactive oxygen species leading to
DNA strand breaks
B. Loss of correction of replication errors causing accumulation
,of point mutations and microsatellite instability
C. Failure of non-homologous end joining, causing chromosome
translocations
D. Enhanced base-excision repair causing hypermutation of
repetitive sequences
Correct Answer
B
Rationales
• Correct (B): Mismatch repair proteins correct replication
errors; loss leads to unrepaired base–base mismatches and
insertion/deletion loops, producing point mutations and
microsatellite instability, which drive tumorigenesis.
• Incorrect (A): Reactive oxygen species cause oxidative DNA
damage but are not the primary consequence of defective
mismatch repair.
• Incorrect (C): Non-homologous end joining repairs double-
strand breaks; mismatch repair defects do not primarily
cause DSB repair failure or translocations.
• Incorrect (D): Base-excision repair corrects small base
lesions; mismatch repair deficiency does not enhance
base-excision repair or produce hypermutation of repeats.
Teaching Point
Mismatch repair failure → replication errors persist → point
mutations and microsatellite instability.
,Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
2
Reference
Ch. 1 — The Cell as a Unit of Health and Disease — The
Genome
Question Stem
A newborn screening shows a homozygous nonsense mutation
in a gene required for nucleotide excision repair (NER). Which
environmental exposure should clinicians advise the family to
strictly avoid to reduce cancer risk?
Options
A. Ionizing radiation (X-rays)
B. Ultraviolet (UV) sunlight exposure
C. High-fat diet
D. Tobacco smoke
Correct Answer
B
Rationales
• Correct (B): NER removes UV-induced bulky pyrimidine
dimers; defective NER makes cells highly sensitive to UV,
markedly increasing skin cancer risk.
, • Incorrect (A): Ionizing radiation primarily causes double-
strand breaks; while harmful, NER deficiency specifically
predisposes to UV-induced damage.
• Incorrect (C): Diet influences cancer risk indirectly but is
not the primary risk in NER deficiency.
• Incorrect (D): Tobacco causes DNA adducts repaired
mainly by NER and other pathways, but UV avoidance is
the most critical immediate protection for NER defects.
Teaching Point
NER deficiency → extreme sensitivity to UV-induced DNA
lesions; avoid sun exposure.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
3
Reference
Ch. 1 — The Cell as a Unit of Health and Disease — Cellular
Housekeeping
Question Stem
A patient with a neurodegenerative disorder shows
accumulation of ubiquitinated protein aggregates in neurons.
Which cellular pathway dysfunction most likely explains this
finding?
