Principles of cancer – pathogenesis MCQs With Answer

Introduction: The Principles of Cancer – Pathogenesis MCQs with Answer is a focused study resource tailored for B. Pharm students preparing for pharmacology and oncology modules. This concise guide covers carcinogenesis stages, tumor biology, oncogenes and tumor suppressor genes, mechanisms of metastasis, angiogenesis, DNA repair defects, viral and environmental carcinogens, epigenetic changes, and tumor microenvironment factors. Emphasis on molecular targets, biomarkers, and pharmacologic implications helps bridge basic science with therapeutic strategies. Designed to boost exam readiness and clinical understanding, the questions reinforce concepts essential for cancer pharmacology and therapeutics. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which of the following best describes initiation in chemical carcinogenesis?

• Reversible promotion of cell proliferation
• Permanent genetic alteration of DNA
• Formation of new blood vessels
• Immune-mediated tumor elimination

Correct Answer: Permanent genetic alteration of DNA

Q2. Knudson’s two-hit hypothesis primarily explains the inheritance pattern of which class of cancer genes?

• Oncogenes activated by point mutations
• Tumor suppressor genes requiring both alleles to be inactivated
• DNA repair genes that are dominant
• Genes encoding growth factors

Correct Answer: Tumor suppressor genes requiring both alleles to be inactivated

Q3. Which protein is most commonly mutated in human cancers and is essential for DNA damage response and apoptosis?

• BRCA1
• p53
• HER2
• VEGF

Correct Answer: p53

Q4. Activation of proto-oncogenes to oncogenes can occur by all of the following EXCEPT:

• Point mutation
• Gene amplification
• Chromosomal translocation
• Methylation of promoter CpG islands

Correct Answer: Methylation of promoter CpG islands

Q5. Which oncogene is commonly associated with chronic myeloid leukemia due to a translocation t(9;22)?

• MYC
• RAS
• BCR-ABL
• TP53

Correct Answer: BCR-ABL

Q6. What is the hallmark metabolic change in many cancer cells known as the Warburg effect?

• Increased oxidative phosphorylation and reduced glycolysis
• Enhanced aerobic glycolysis despite oxygen availability
• Complete reliance on fatty acid oxidation
• Decreased glucose uptake

Correct Answer: Enhanced aerobic glycolysis despite oxygen availability

Q7. Which enzyme is frequently reactivated in cancer cells to maintain telomere length and enable replicative immortality?

• DNA polymerase beta
• Telomerase (hTERT)
• Topoisomerase II
• Telomere exonuclease

Correct Answer: Telomerase (hTERT)

Q8. Which process describes epithelial tumor cells acquiring mesenchymal traits to facilitate invasion?

• Angiogenesis
• Epithelial–mesenchymal transition (EMT)
• Apoptosis
• Sensitization

Correct Answer: Epithelial–mesenchymal transition (EMT)

Q9. Microsatellite instability (MSI) is most directly caused by defects in which cellular mechanism?

• Mismatch repair (MMR) system
• Homologous recombination repair
• Nucleotide excision repair
• Base excision repair

Correct Answer: Mismatch repair (MMR) system

Q10. Which viral infection is strongly linked to cervical cancer through E6/E7 oncoproteins?

• Hepatitis B virus (HBV)
• Human papillomavirus (HPV)
• Epstein–Barr virus (EBV)
• Human T-cell lymphotropic virus (HTLV-1)

Correct Answer: Human papillomavirus (HPV)

Q11. Which growth factor is the principal mediator of angiogenesis in tumors?

• Vascular endothelial growth factor (VEGF)
• Transforming growth factor-beta (TGF-β)
• Interleukin-2 (IL-2)
• Epidermal growth factor (EGF)

Correct Answer: Vascular endothelial growth factor (VEGF)

Q12. Which molecular alteration leads to HER2-driven breast cancer?

• Point mutation in HER2 leading to inactivity
• Amplification/overexpression of HER2 (ERBB2)
• Methylation of HER2 promoter silencing expression
• Chromosomal deletion of ERBB2 locus

Correct Answer: Amplification/overexpression of HER2 (ERBB2)

Q13. Loss of function mutations in Rb protein primarily affect which cell cycle checkpoint?

• G2/M checkpoint
• Spindle assembly checkpoint
• G1/S checkpoint
• S-phase checkpoint

Correct Answer: G1/S checkpoint

Q14. Which tumor suppressor genes are most commonly associated with hereditary breast and ovarian cancer?

• BRCA1 and BRCA2
• TP53 and RB1
• KRAS and NRAS
• APC and PTEN

Correct Answer: BRCA1 and BRCA2

Q15. Clonal evolution in tumors refers to:

• Uniform genetic makeup of all tumor cells
• Selection of subclones with advantageous mutations over time
• Reversion of malignant cells to normal phenotype
• Exclusive reliance on epigenetic changes without mutation

Correct Answer: Selection of subclones with advantageous mutations over time

Q16. Which proteases facilitate extracellular matrix degradation during tumor invasion?

• Caspases
• Matrix metalloproteinases (MMPs)
• DNA nucleases
• Serine protease inhibitors

Correct Answer: Matrix metalloproteinases (MMPs)

Q17. PD-1/PD-L1 interactions in the tumor microenvironment primarily enable cancer cells to:

• Induce differentiation of tumor cells
• Evade immune destruction by inhibiting T cells
• Increase angiogenesis
• Promote apoptosis of cancer cells

Correct Answer: Evade immune destruction by inhibiting T cells

Q18. Which carcinogen is a classic example of a chemical that requires metabolic activation by cytochrome P450 to become mutagenic?

• UV radiation
• Benzo[a]pyrene (from tobacco smoke)
• Ionizing radiation
• HPV E6 protein

Correct Answer: Benzo[a]pyrene (from tobacco smoke)

Q19. Which genetic instability is characterized by gains and losses of whole chromosomes or large chromosome segments?

• Microsatellite instability (MSI)
• Chromosomal instability (CIN)
• Single nucleotide polymorphism (SNP) instability
• Telomeric instability only

Correct Answer: Chromosomal instability (CIN)

Q20. Which tumor marker is most commonly elevated in hepatocellular carcinoma and certain germ cell tumors?

• Carcinoembryonic antigen (CEA)
• Alpha-fetoprotein (AFP)
• Prostate-specific antigen (PSA)
• CA-125

Correct Answer: Alpha-fetoprotein (AFP)

Q21. The main function of p16INK4a (CDKN2A) is to:

• Activate telomerase
• Inhibit cyclin-dependent kinases to regulate G1/S transition
• Promote angiogenesis
• Repair double-strand DNA breaks

Correct Answer: Inhibit cyclin-dependent kinases to regulate G1/S transition

Q22. Which mechanism is a common way for oncogenic activation of RAS?

• Promoter hypermethylation
• Point mutation leading to constitutive GTP binding
• Loss of heterozygosity at RAS locus
• Increased proteasomal degradation

Correct Answer: Point mutation leading to constitutive GTP binding

Q23. Field cancerization refers to:

• Invasion of tumor into surrounding tissue
• Widespread pre-neoplastic genetic alterations in a tissue area increasing cancer risk
• Formation of angiogenic fields around tumor
• Localized immune response to cancer cells

Correct Answer: Widespread pre-neoplastic genetic alterations in a tissue area increasing cancer risk

Q24. Which of the following is a hallmark of malignant transformation relating to tissue energy supply?

• Decreased need for nutrients
• Induction of angiogenesis to support growth
• Complete independence from blood supply
• Suppression of glycolysis

Correct Answer: Induction of angiogenesis to support growth

Q25. Which DNA repair pathway repairs UV-induced thymine dimers?

• Mismatch repair (MMR)
• Nucleotide excision repair (NER)
• Homologous recombination (HR)
• Base excision repair (BER)

Correct Answer: Nucleotide excision repair (NER)

Q26. Which inherited syndrome is characterized by germline mutations in DNA mismatch repair genes leading to colorectal cancer?

• Li-Fraumeni syndrome
• Lynch syndrome (HNPCC)
• Familial adenomatous polyposis (FAP)
• BRCA-associated syndrome

Correct Answer: Lynch syndrome (HNPCC)

Q27. Oncogene addiction refers to:

• Dependence of cancer cells on a single overactive oncogenic pathway for survival
• Addiction of patients to chemotherapeutic drugs
• Immune system dependence on tumor antigens
• Requirement of stromal cells for tumor growth

Correct Answer: Dependence of cancer cells on a single overactive oncogenic pathway for survival

Q28. Which biomarker is most useful for monitoring prostate cancer progression?

• CA 19-9
• PSA (Prostate-specific antigen)
• AFP
• Chromogranin A

Correct Answer: PSA (Prostate-specific antigen)

Q29. Which process allows tumor cells to survive detachment from the extracellular matrix and resist anoikis?

• Activation of apoptosis pathways
• Upregulation of survival signaling such as PI3K/AKT
• Reduction of telomerase activity
• Enhanced gap junction communication

Correct Answer: Upregulation of survival signaling such as PI3K/AKT

Q30. Which oncogene family encodes small GTPases frequently mutated in cancers like pancreatic carcinoma?

• MYC family
• RAS family
• ERBB family
• FLT family

Correct Answer: RAS family

Q31. Which cellular process is impaired when BRCA1/BRCA2 are mutated, increasing cancer risk?

• Mismatch repair
• Homologous recombination repair of double-strand breaks
• Base excision repair
• Protein folding in the ER

Correct Answer: Homologous recombination repair of double-strand breaks

Q32. Epigenetic silencing of a tumor suppressor gene is most commonly achieved by:

• Gene amplification
• Promoter CpG island hypermethylation
• Chromosomal translocation
• Point mutation causing frameshift

Correct Answer: Promoter CpG island hypermethylation

Q33. Which hallmark of cancer enables tumor cells to avoid programmed cell death?

• Evading growth suppressors
• Resisting cell death (apoptosis)
• Sustaining proliferative signaling
• Genome instability

Correct Answer: Resisting cell death (apoptosis)

Q34. Which cytokine or transcription factor is stabilized in hypoxic tumor regions and drives angiogenesis?

• NF-κB
• HIF-1α (Hypoxia-inducible factor 1-alpha)
• p53
• STAT3

Correct Answer: HIF-1α (Hypoxia-inducible factor 1-alpha)

Q35. Which viral oncogene product targets p53 for degradation in HPV-related cancers?

• EBNA1
• E6
• Tax
• HBx

Correct Answer: E6

Q36. Carcinoma in situ is best described as:

• Invasive cancer penetrating basement membrane
• Localized pre-invasive neoplasm confined above the basement membrane
• Metastatic tumor in distant organ
• Benign hyperplasia

Correct Answer: Localized pre-invasive neoplasm confined above the basement membrane

Q37. Which class of genes, when inactivated, often leads to failure of apoptosis and increased cancer susceptibility?

• Proto-oncogenes
• Tumor suppressor genes
• Ribosomal protein genes
• Housekeeping metabolic enzymes

Correct Answer: Tumor suppressor genes

Q38. Metastatic colonization at preferred sites (organotropism) is best explained by which concept?

• Clonal uniformity
• Seed and soil hypothesis
• Two-hit hypothesis
• Oncogene addiction

Correct Answer: Seed and soil hypothesis

Q39. Which hormone-related receptor overexpression is a therapeutic target in some breast cancers?

• Estrogen receptor (ER)
• Insulin receptor
• Thyroid hormone receptor
• Glucocorticoid receptor

Correct Answer: Estrogen receptor (ER)

Q40. Which molecular change is characteristic of chromothripsis observed in some aggressive tumors?

• Gradual accumulation of single nucleotide changes
• Massive chromosomal rearrangements occurring in a single catastrophic event
• Loss of telomerase activity leading to senescence
• Uniform methylation across the genome

Correct Answer: Massive chromosomal rearrangements occurring in a single catastrophic event

Q41. Which tumor marker is associated with colorectal cancer and is used for monitoring recurrence?

• CA-125
• CA 19-9
• Carcinoembryonic antigen (CEA)
• AFP

Correct Answer: Carcinoembryonic antigen (CEA)

Q42. Which pathway is commonly activated downstream of receptor tyrosine kinases and promotes cell growth and survival?

• PI3K/AKT/mTOR pathway
• Ubiquitin–proteasome pathway
• Base excision repair pathway
• Intrinsic apoptotic pathway only

Correct Answer: PI3K/AKT/mTOR pathway

Q43. Which of the following best characterizes paraneoplastic syndromes?

• Direct invasion of neighboring organs by tumor
• Remote systemic effects of tumors not directly related to tumor mass or metastasis
• Local inflammation due to tumor necrosis
• Standard metastatic spread

Correct Answer: Remote systemic effects of tumors not directly related to tumor mass or metastasis

Q44. Which microRNA-related mechanism can contribute to oncogenesis?

• Overexpression of tumor-suppressive microRNAs
• Downregulation of oncogenic microRNAs only
• Dysregulated microRNAs that suppress tumor suppressor genes or activate oncogenes
• MicroRNAs do not play a role in cancer

Correct Answer: Dysregulated microRNAs that suppress tumor suppressor genes or activate oncogenes

Q45. Which change is typical of tumor cells that have become resistant to chemotherapy via drug efflux?

• Upregulation of P-glycoprotein (MDR1/ABCB1)
• Decreased DNA repair capacity
• Loss of angiogenic signaling
• Reduced expression of detoxifying enzymes

Correct Answer: Upregulation of P-glycoprotein (MDR1/ABCB1)

Q46. Which mechanism explains how chronic inflammation promotes carcinogenesis?

• Decreased cell turnover preventing mutation accumulation
• Production of reactive oxygen and nitrogen species causing DNA damage and promoting proliferation
• Immediate elimination of damaged cells
• Suppression of angiogenesis

Correct Answer: Production of reactive oxygen and nitrogen species causing DNA damage and promoting proliferation

Q47. Which genetic change is characteristic of familial adenomatous polyposis (FAP)?

• Germline mutation of APC gene leading to multiple colorectal polyps
• Lynch syndrome related MMR mutations
• BRCA1 mutation with breast cancer predisposition
• p53 germline mutation causing sarcomas

Correct Answer: Germline mutation of APC gene leading to multiple colorectal polyps

Q48. Which signaling molecule released by tumor-associated macrophages often supports tumor progression?

• Interferon-gamma (IFN-γ)
• Tumor necrosis factor-alpha (TNF-α) with protumor effects depending on context
• Granzyme B exclusively promoting tumor death
• Complement factor C9 only

Correct Answer: Tumor necrosis factor-alpha (TNF-α) with protumor effects depending on context

Q49. Which mechanism allows tumors to generate heterogeneity that complicates treatment?

• Stable genome with no mutations
• Continuous acquisition of genetic and epigenetic changes creating diverse subclones
• Uniform expression of a single tumor antigen
• Elimination of all stem-like tumor cells only

Correct Answer: Continuous acquisition of genetic and epigenetic changes creating diverse subclones

Q50. Which targeted therapy principle exploits the reliance of certain tumors on specific oncogenic drivers?

• Non-specific cytotoxic chemotherapy only
• Targeted inhibition of key oncogenic proteins (e.g., BCR-ABL, EGFR, HER2)
• Radiation that targets all dividing cells equally
• Supportive care without direct targeting

Correct Answer: Targeted inhibition of key oncogenic proteins (e.g., BCR-ABL, EGFR, HER2)

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