39 Year 3: General Pathology exam questions on Oncopathology Hallmarks of Cancer MCQs for medical students. Includes MCQs, answers, explanations and written que
This MCQ set contains 39 questions on Oncopathology Hallmarks of Cancer MCQs in the Year 3: General Pathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.
Correct answer: C – Failure of HIF-1α ubiquitination in normoxic conditions
In VHL syndrome, mutated VHL protein cannot bind and ubiquitinate HIF-1α even in normoxic conditions, leading to constitutive HIF-1α stabilization and VEGF transcription, promoting angiogenesis.
Correct answer: B – 1-2 mm
Tumors cannot enlarge beyond 1-2 mm in diameter without angiogenesis due to the maximal diffusion distance for oxygen, nutrients, and waste from blood vessels.
Correct answer: C – Angiostatin
Angiostatin is produced by proteolytic cleavage of plasminogen. Endostatin comes from collagen cleavage, and vasculostatin from transthyretin cleavage.
Correct answer: B – E-cadherin
E-cadherin functions as an intercellular adhesion molecule and transmits antigrowth signals by sequestering β-catenin. Its function is lost in almost all epithelial cancers.
Correct answer: C – Mismatch repair defects with microsatellite instability
HNPCC is caused by defects in mismatch repair genes, leading to microsatellite instability (MSI) characterized by changes in length of short tandem repeating sequences throughout the genome.
Correct answer: B – Thrombospondin-1 (TSP-1)
Normal p53 induces synthesis of TSP-1, the prototypical angiogenesis inhibitor, maintaining vascular quiescence in early tumor growth.
Correct answer: C – MMP-9
MMP-9 is a gelatinase that cleaves type IV collagen of epithelial and vascular basement membranes and stimulates release of VEGF from ECM-sequestered pools.
Correct answer: B – Nucleotide excision repair
Xeroderma pigmentosum involves defects in nucleotide excision repair, leading to inability to repair UV-induced pyrimidine dimers and increased risk of skin cancers.
Correct answer: C – SNAIL and TWIST
SNAIL and TWIST transcription factors suppress E-cadherin expression, leading to loss of intercellular adhesion and promoting tumor cell invasion and metastasis.
Correct answer: A – 2
Aerobic glycolysis produces only 2 ATP molecules per glucose molecule, compared to 36 ATP from mitochondrial oxidative phosphorylation, yet supports rapid tumor growth.
Correct answer: C – PET scan
PET scanning uses 18F-fluorodeoxyglucose, a nonmetabolizable glucose derivative, to visualize the increased glucose uptake characteristic of tumors exhibiting the Warburg effect.
Correct answer: A – Perfusion supplies nutrients AND newly formed endothelial cells secrete growth factors
Neovascularization has a dual effect: perfusion supplies oxygen and nutrients, while newly formed endothelial cells stimulate tumor growth by secreting growth factors like IGF, PDGF, and GM-CSF.
Correct answer: B – Organs expressing CXCL12 and CCL21
Breast cancer cells expressing CXCR4 and CCR7 metastasize to organs highly expressing their ligands (CXCL12 and CCL21), demonstrating organ tropism through chemokine receptor-ligand interactions.
Correct answer: B – BRCA1 and BRCA2
BRCA1 and BRCA2 are involved in DNA repair through homologous recombination and are mutated in familial breast cancers, increasing cancer susceptibility.
Correct answer: C – Lack of oxygen prevents VHL recognition of HIF-1α
In hypoxia, lack of oxygen prevents VHL from recognizing and binding HIF-1α, preventing its ubiquitination and degradation, allowing HIF-1α to translocate to the nucleus and activate VEGF transcription.
Correct answer: C – Loosening of tumor cell-to-cell contacts
The first step in the metastatic cascade is loosening of tumor cell-to-cell contacts, primarily through loss of E-cadherin function, before cells can invade the ECM.
Correct answer: B – They undergo apoptosis
Loss of adhesion in normal cells leads to induction of apoptosis, while tumor cells are resistant to this form of cell death, allowing them to survive during metastasis.
Correct answer: C – Ataxia-telangiectasia
Ataxia-telangiectasia involves defects in homologous recombination DNA repair and is characterized by hypersensitivity to DNA-damaging agents like ionizing radiation.
Correct answer: C – Inactivation of APC
In colon carcinogenesis, inactivation of the APC tumor suppressor gene typically occurs first, followed by RAS activation, then loss of chromosome 18q, and finally loss of TP53.
Correct answer: B – Nonpermissive microenvironment
Although well vascularized, skeletal muscles provide a nonpermissive microenvironment for tumor cell growth, demonstrating that vascularization alone is insufficient for metastasis.
Correct answer: B – Autocrine motility factors
Tumor cells secrete autocrine motility factors that act on themselves to potentiate and direct migration through degraded basement membranes and matrix zones during invasion.
Correct answer: B – They exhibit altered gene expression that can promote tumorigenesis
Tumor-associated fibroblasts exhibit altered expression of genes encoding ECM molecules, proteases, protease inhibitors, and growth factors, actively participating in creating a microenvironment that can promote tumorigenesis.
Correct answer: B – It is bound by VHL, ubiquitinated, and destroyed
In normoxic settings, VHL protein binds to HIF-1α, leading to its ubiquitination and subsequent destruction, preventing inappropriate angiogenesis activation.
Correct answer: B – Proteases acting on collagen
Endostatin is produced by proteolytic cleavage of collagen by various proteases, serving as one of the potent angiogenesis inhibitors that balance pro-angiogenic signals.
Correct answer: B – Leaky, dilated with haphazard connections
Tumor vasculature is abnormal, characterized by leaky, dilated vessels with haphazard patterns of connection, unlike the organized structure of normal blood vessels.