Principles of cancer – etiology MCQs With Answer

Principles of cancer – etiology MCQs With Answer

The principles of cancer and etiology are essential for B. Pharm students preparing for pharmacology, toxicology, and oncology modules. This concise, SEO-rich introduction explains carcinogenesis mechanisms, risk factors, chemical and viral carcinogens, genetic mutations, and tumor-promoting processes. Understanding initiation, promotion, progression, oncogenes, tumor suppressors, DNA repair defects, and environmental exposures helps pharmacists evaluate drug safety and counsel on prevention. Key terms include cancer etiology, carcinogenesis, oncogenes, tumor suppressor genes, chemical carcinogens, and viral oncology. Practical knowledge of etiology supports rational therapy selection, pharmacovigilance, and public health interventions. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the term for the process by which normal cells transform into cancer cells?

• Metastasis
• Carcinogenesis
• Apoptosis
• Differentiation

Correct Answer: Carcinogenesis

Q2. Which of the following best describes an initiator in chemical carcinogenesis?

• A compound that promotes proliferation without DNA damage
• A compound that causes irreversible DNA damage leading to mutation
• An immunological factor that eliminates mutated cells
• A compound that repairs DNA lesions

Correct Answer: A compound that causes irreversible DNA damage leading to mutation

Q3. Which gene type, when mutated to a gain-of-function, commonly drives oncogenesis?

• Tumor suppressor gene
• Housekeeping gene
• Oncogene
• DNA repair gene

Correct Answer: Oncogene

Q4. Loss-of-function mutations in which gene are most associated with impaired cell cycle checkpoint control?

• p53
• EGFR
• HER2
• RAS

Correct Answer: p53

Q5. Which viral infection is strongly linked to cervical cancer?

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

Correct Answer: Human papillomavirus (HPV)

Q6. Aflatoxin exposure is classically associated with which cancer type?

• Bladder cancer
• Liver (hepatocellular) carcinoma
• Lung cancer
• Leukemia

Correct Answer: Liver (hepatocellular) carcinoma

Q7. What is the primary mechanism by which UV radiation contributes to skin cancer?

• Induction of double-strand breaks only
• Direct formation of thymine dimers causing DNA mutations
• Inhibiting angiogenesis
• Increasing telomerase activity

Correct Answer: Direct formation of thymine dimers causing DNA mutations

Q8. Which chemical is a well-known occupational carcinogen linked to angiosarcoma of the liver?

• Benzene
• Vinyl chloride
• Asbestos
• Formaldehyde

Correct Answer: Vinyl chloride

Q9. The Ames test is used to assess what property of a chemical?

• Carcinogenicity in humans directly
• Ability to cause mutagenic changes in bacterial DNA
• Teratogenic potential in embryos
• Pharmacokinetic half-life in mammals

Correct Answer: Ability to cause mutagenic changes in bacterial DNA

Q10. Which of the following is a tumor suppressor gene commonly mutated in hereditary breast and ovarian cancer?

• KRAS
• BRCA1
• MYC
• HER2

Correct Answer: BRCA1

Q11. What is the hallmark of cancer that describes the ability of tumor cells to recruit new blood vessels?

• Evading growth suppressors
• Sustained proliferative signaling
• Inducing angiogenesis
• Genome instability

Correct Answer: Inducing angiogenesis

Q12. Which carcinogen metabolized by cytochrome P450 to a reactive species is found in cigarette smoke?

• Aflatoxin B1
• Benzo[a]pyrene
• Vinyl chloride
• Asbestos fibers

Correct Answer: Benzo[a]pyrene

Q13. Which mechanism allows cancer cells to escape immune surveillance?

• Upregulation of MHC class I expression
• Secretion of immunosuppressive cytokines like TGF-β
• Increased antigen presentation
• Enhanced natural killer cell activity

Correct Answer: Secretion of immunosuppressive cytokines like TGF-β

Q14. Chronic infection with Helicobacter pylori is most strongly associated with which cancer?

• Gastric (stomach) cancer
• Colon cancer
• Pancreatic cancer
• Esophageal adenocarcinoma

Correct Answer: Gastric (stomach) cancer

Q15. Which process describes spread of cancer cells through the bloodstream?

• Local invasion
• Lymphatic dissemination
• Hematogenous metastasis
• In situ transformation

Correct Answer: Hematogenous metastasis

Q16. Which carcinogen class is known to cause bladder cancer and is derived from aromatic amines?

• Polycyclic aromatic hydrocarbons
• Aromatic amines like benzidine
• Alkylating agents
• Organophosphates

Correct Answer: Aromatic amines like benzidine

Q17. Epigenetic alterations in cancer often include:

• DNA sequence deletions only
• DNA promoter hypermethylation and histone modification
• Only point mutations in exon regions
• Increase in genome size

Correct Answer: DNA promoter hypermethylation and histone modification

Q18. Which oncogene product is a small GTPase frequently mutated in human cancers?

• TP53
• RAS
• BRCA2
• PTEN

Correct Answer: RAS

Q19. Chronic exposure to asbestos fibers is most closely linked to which malignancy?

• Mesothelioma
• Hepatocellular carcinoma
• Leukemia
• Melanoma

Correct Answer: Mesothelioma

Q20. Secondary malignancies following certain chemotherapy are most commonly associated with which drug class?

• Antimetabolites
• Alkylating agents
• Monoclonal antibodies
• Taxanes

Correct Answer: Alkylating agents

Q21. Which measurement assesses the probability of developing cancer in a population due to exposure?

• Half-life
• Relative risk or attributable risk
• Volume of distribution
• Bioavailability

Correct Answer: Relative risk or attributable risk

Q22. The multistage model of carcinogenesis includes which sequence?

• Initiation, promotion, progression
• Metastasis, initiation, apoptosis
• Promotion, repair, differentiation
• Apoptosis, necrosis, inflammation

Correct Answer: Initiation, promotion, progression

Q23. Which tumor marker is often elevated in prostate cancer?

• CEA
• AFP
• PSA
• CA-125

Correct Answer: PSA

Q24. Reactive oxygen species contribute to carcinogenesis primarily by:

• Enhancing DNA repair mechanisms
• Causing oxidative DNA damage and mutations
• Inhibiting cell proliferation
• Blocking angiogenesis

Correct Answer: Causing oxidative DNA damage and mutations

Q25. Oncogenic viruses can contribute to cancer by:

• Integrating viral DNA and expressing oncogenic proteins
• Enhancing DNA repair fidelity
• Always causing immediate cell death
• Decreasing mutation rates

Correct Answer: Integrating viral DNA and expressing oncogenic proteins

Q26. Which dietary factor is linked to increased colon cancer risk?

• High fiber intake
• Low red meat consumption
• High consumption of processed and red meat
• Frequent intake of fruits and vegetables

Correct Answer: High consumption of processed and red meat

Q27. The “two-hit” hypothesis applies to which category of genes?

• Proto-oncogenes
• Tumor suppressor genes
• Housekeeping genes
• Oncoviruses

Correct Answer: Tumor suppressor genes

Q28. Chronic hepatitis B or C infection increases risk primarily for which cancer?

• Pancreatic cancer
• Hepatocellular carcinoma
• Prostate cancer
• Thyroid carcinoma

Correct Answer: Hepatocellular carcinoma

Q29. Which environmental exposure is strongly linked to lung cancer in non-smokers?

• Radon gas
• Asbestos only
• UV radiation
• High-fiber diet

Correct Answer: Radon gas

Q30. Loss of heterozygosity (LOH) in tumor DNA indicates:

• Enhanced immune recognition
• Deletion or inactivation of a tumor suppressor allele
• Activation of viral oncogenes
• Improved DNA repair capacity

Correct Answer: Deletion or inactivation of a tumor suppressor allele

Q31. Which molecular change is commonly seen in early stages of lung cancer linked to smoking?

• Promoter hypermethylation of tumor suppressor genes
• Increase in telomere length only
• Loss of all copy number variations
• Complete absence of mutations

Correct Answer: Promoter hypermethylation of tumor suppressor genes

Q32. The term “field cancerization” refers to:

• Metastasis to distant organs
• Widespread premalignant changes in an epithelial surface
• Immune-mediated tumor rejection
• Single-cell transformation only

Correct Answer: Widespread premalignant changes in an epithelial surface

Q33. Which inherited mutation markedly increases lifetime risk of breast and ovarian cancer?

• TP53 R175H only
• BRCA1/BRCA2 mutations
• KRAS G12D mutation
• EGFR amplification

Correct Answer: BRCA1/BRCA2 mutations

Q34. Which mechanism is a common cause of oncogene activation?

• Chromosomal translocation creating fusion proteins
• Complete loss of gene function
• Increased autophagy only
• Enhanced DNA methylation of the gene promoter

Correct Answer: Chromosomal translocation creating fusion proteins

Q35. Which cancer risk is increased by persistent gastroesophageal reflux disease (GERD)?

• Squamous cell carcinoma of larynx
• Adenocarcinoma of the esophagus (Barrett’s-related)
• Hepatocellular carcinoma
• Renal cell carcinoma

Correct Answer: Adenocarcinoma of the esophagus (Barrett’s-related)

Q36. Which laboratory assay directly measures DNA repair capacity or nucleotide excision repair defects?

• Western blot for p53 only
• Host-cell reactivation assay
• Serum tumor marker level
• Complete blood count

Correct Answer: Host-cell reactivation assay

Q37. Chronic inflammation contributes to carcinogenesis by:

• Decreasing cell proliferation
• Producing reactive species and growth factors that promote mutation and proliferation
• Enhancing DNA repair fidelity
• Eliminating premalignant clones

Correct Answer: Producing reactive species and growth factors that promote mutation and proliferation

Q38. Which biomolecule alteration often enables immortality of cancer cells?

• Activation of telomerase
• Downregulation of glycolysis
• Use of oxidative phosphorylation only
• Decrease in growth factor receptors

Correct Answer: Activation of telomerase

Q39. Which population-level intervention most reduces viral-related cancers (e.g., cervical cancer)?

• Antioxidant supplements
• Vaccination against oncogenic viruses (e.g., HPV vaccine)
• High-dose chemotherapy for everyone
• Universal antibiotic prophylaxis

Correct Answer: Vaccination against oncogenic viruses (e.g., HPV vaccine)

Q40. Which class of environmental agents requires metabolic activation to become carcinogenic?

• Direct-acting alkylating agents
• Procarcinogens like polycyclic aromatic hydrocarbons
• Ionizing radiation
• Mechanical irritants

Correct Answer: Procarcinogens like polycyclic aromatic hydrocarbons

Q41. What does “latency period” refer to in cancer epidemiology?

• Time from exposure to detectable cancer development
• Time for chemotherapy infusion
• Duration of tumor regression
• Time between metastases only

Correct Answer: Time from exposure to detectable cancer development

Q42. Which biomarker is commonly elevated in hepatocellular carcinoma?

• CA 19-9
• Alpha-fetoprotein (AFP)
• Prostate-specific antigen (PSA)
• CA-125

Correct Answer: Alpha-fetoprotein (AFP)

Q43. Aflatoxin B1 induces characteristic mutation in which tumor suppressor gene in hepatocellular carcinoma?

• KRAS codon 12 mutation
• p53 codon 249 (AGG to AGT) mutation
• EGFR amplification
• BRCA2 frameshift

Correct Answer: p53 codon 249 (AGG to AGT) mutation

Q44. Which occupational exposure is associated with bladder cancer?

• Exposure to aromatic amines in dyes and rubber industries
• High-dose vitamin C intake
• Indoor air pollution from cooking oil only
• Frequent cellphone use

Correct Answer: Exposure to aromatic amines in dyes and rubber industries

Q45. Which DNA repair pathway is primarily responsible for fixing UV-induced thymine dimers?

• Mismatch repair
• Nucleotide excision repair (NER)
• Homologous recombination
• Base excision repair

Correct Answer: Nucleotide excision repair (NER)

Q46. HER2 amplification is most clinically relevant in which cancer?

• Colorectal cancer
• Breast cancer
• Acute lymphoblastic leukemia
• Melanoma

Correct Answer: Breast cancer

Q47. Which factor decreases cancer risk based on epidemiological evidence?

• Tobacco smoking
• Regular physical activity and healthy diet
• Excessive alcohol consumption
• Chronic UV overexposure

Correct Answer: Regular physical activity and healthy diet

Q48. Carcinogen dose-response relationships that show no safe threshold are typical of which kind?

• Non-cumulative dose of vitamins
• Linear no-threshold model often used for genotoxic carcinogens
• Hormetic beneficial low-dose response only
• Strict threshold-only toxicants

Correct Answer: Linear no-threshold model often used for genotoxic carcinogens

Q49. Which enzyme family is crucial for metabolic activation and detoxification of many carcinogens?

• Caspases
• Cytochrome P450 monooxygenases
• DNA polymerases
• Proteases

Correct Answer: Cytochrome P450 monooxygenases

Q50. Which preventive strategy can reduce incidence of hepatocellular carcinoma worldwide?

• HPV vaccination
• HBV vaccination and control of HCV infection
• Daily aspirin for all adults
• Elimination of all sunlight exposure

Correct Answer: HBV vaccination and control of HCV infection

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