Introduction: Antineoplastic agents are drugs used in chemotherapy to treat cancer by targeting rapidly dividing cells. This topic covers classification (alkylating agents, antimetabolites, plant alkaloids, topoisomerase inhibitors, antitumor antibiotics, platinum complexes, monoclonal antibodies, targeted therapies), structure–activity relationships (SAR), mechanisms of action (DNA alkylation, intercalation, enzyme inhibition, microtubule disruption, kinase blockade), clinical uses, resistance mechanisms, and major toxicities. Emphasis on SAR helps predict potency and selectivity while mechanism knowledge guides combination regimens and toxicity management. This concise, keyword-rich review prepares B. Pharm students for applied pharmacology and therapeutics. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which of the following is a classical example of an alkylating agent class?
- Nitrogen mustards
- Antimetabolites
- Monoclonal antibodies
- Topoisomerase inhibitors
Correct Answer: Nitrogen mustards
Q2. Which SAR feature is critical for classical nitrogen mustard activity?
- Presence of an aziridine ring
- Two chloroethyl groups capable of forming aziridinium ion
- A planar tetracyclic ring system
- A terminal fluorine at C-5 of uracil
Correct Answer: Two chloroethyl groups capable of forming aziridinium ion
Q3. Antimetabolites exert anticancer effects primarily by:
- Intercalating into DNA
- Alkylating guanine bases
- Mimicking natural nucleotides and inhibiting nucleotide synthesis or incorporation
- Inhibiting microtubule depolymerization
Correct Answer: Mimicking natural nucleotides and inhibiting nucleotide synthesis or incorporation
Q4. Which drug is a topoisomerase I inhibitor commonly used in solid tumors?
- Etoposide
- Topotecan
- Doxorubicin
- Vincristine
Correct Answer: Topotecan
Q5. Vinca alkaloids like vincristine act by:
- Stabilizing microtubules and preventing depolymerization
- Inhibiting DNA topoisomerase II
- Binding tubulin and preventing microtubule polymerization
- Intercalating between DNA base pairs
Correct Answer: Binding tubulin and preventing microtubule polymerization
Q6. The primary mechanism of action of taxanes is:
- Microtubule stabilization leading to mitotic arrest
- DNA cross-linking at N7 of guanine
- Folate antagonism
- Inhibition of dihydrofolate reductase
Correct Answer: Microtubule stabilization leading to mitotic arrest
Q7. Platinum complexes (e.g., cisplatin) kill cancer cells mainly by:
- Inhibiting thymidylate synthase
- Forming intrastrand and interstrand DNA cross-links
- Blocking microtubule assembly
- Acting as monoclonal antibodies against growth factor receptors
Correct Answer: Forming intrastrand and interstrand DNA cross-links
Q8. The anthracycline doxorubicin’s dose-limiting toxicity is primarily due to:
- Renal tubular damage
- Cardiotoxicity from free radical generation and iron-mediated damage
- Pulmonary fibrosis from bleomycin-like mechanism
- Severe hemorrhagic cystitis
Correct Answer: Cardiotoxicity from free radical generation and iron-mediated damage
Q9. Methotrexate inhibits which enzyme important for nucleotide synthesis?
- Thymidylate synthase
- DNA polymerase
- Dihydrofolate reductase (DHFR)
- Topoisomerase I
Correct Answer: Dihydrofolate reductase (DHFR)
Q10. 5-Fluorouracil (5-FU) kills cells primarily by:
- Direct DNA alkylation
- Inhibition of topoisomerase II
- Inhibition of thymidylate synthase after conversion to FdUMP
- Disruption of microtubule dynamics
Correct Answer: Inhibition of thymidylate synthase after conversion to FdUMP
Q11. Which mechanism is a common basis for multidrug resistance in cancer chemotherapy?
- Decreased drug efflux via reduced P-glycoprotein expression
- Increased activation of prodrugs
- Overexpression of P-glycoprotein (MDR1) leading to increased drug efflux
- Enhanced drug uptake through increased transporters
Correct Answer: Overexpression of P-glycoprotein (MDR1) leading to increased drug efflux
Q12. Which class of antineoplastic agents is primarily S-phase specific?
- Alkylating agents
- Antimetabolites
- Platinum complexes
- Alkaloids that bind tubulin
Correct Answer: Antimetabolites
Q13. Rituximab, a monoclonal antibody used in lymphoma, targets which antigen?
- HER2/neu
- EGFR
- CD20
- VEGF
Correct Answer: CD20
Q14. Imatinib’s primary molecular target in chronic myeloid leukemia is:
- mTOR
- BCR-ABL tyrosine kinase
- VEGF receptor
- Topoisomerase II
Correct Answer: BCR-ABL tyrosine kinase
Q15. Bleomycin’s major toxicity that limits its use is:
- Severe cardiomyopathy
- Nephrotoxicity leading to renal failure
- Pulmonary fibrosis
- Hemorrhagic cystitis
Correct Answer: Pulmonary fibrosis
Q16. The dose-limiting toxicity of cisplatin is classically:
- Cardiotoxicity
- Nephrotoxicity
- Severe hyponatremia
- Hepatotoxicity
Correct Answer: Nephrotoxicity
Q17. 6-Mercaptopurine requires activation by which enzyme to exert cytotoxicity?
- Thymidine kinase
- HGPRT (hypoxanthine-guanine phosphoribosyltransferase)
- Dihydrofolate reductase
- Cytochrome P450 3A4
Correct Answer: HGPRT (hypoxanthine-guanine phosphoribosyltransferase)
Q18. Etoposide’s anticancer effect is mainly due to inhibition of:
- Topoisomerase I leading to single-strand breaks
- Topoisomerase II causing double-strand DNA breaks
- Dihydrofolate reductase
- Microtubule polymerization
Correct Answer: Topoisomerase II causing double-strand DNA breaks
Q19. Which antineoplastic agent intercalates DNA and generates reactive oxygen species?
- Bleomycin
- Doxorubicin
- Vinblastine
- 5-Fluorouracil
Correct Answer: Doxorubicin
Q20. Which drug contains an aziridine-containing structure and acts as a bioreductive alkylator?
- Nitrogen mustard
- Mitomycin C
- Cisplatin
- Methotrexate
Correct Answer: Mitomycin C
Q21. A key SAR feature that enables anthracyclines to intercalate DNA is:
- An aliphatic side chain with a terminal amine
- A planar, polycyclic tetracyclic aromatic ring system
- Two chloroethyl groups
- A phosphorylated sugar moiety
Correct Answer: A planar, polycyclic tetracyclic aromatic ring system
Q22. Vincristine is commonly included in combination regimens for which cancer in pediatrics?
- Acute lymphoblastic leukemia (ALL)
- Renal cell carcinoma
- Prostate cancer
- Hepatocellular carcinoma
Correct Answer: Acute lymphoblastic leukemia (ALL)
Q23. Monoclonal antibodies mediate tumor cell killing by mechanisms including:
- Only direct DNA alkylation
- ADCC (antibody-dependent cellular cytotoxicity) and complement-dependent cytotoxicity
- Irreversible inhibition of dihydrofolate reductase
- Microtubule depolymerization
Correct Answer: ADCC (antibody-dependent cellular cytotoxicity) and complement-dependent cytotoxicity
Q24. Which of the following is an S-phase specific cytosine nucleoside analog used in acute myeloid leukemia?
- Cytarabine (Ara-C)
- Cisplatin
- Vinblastine
- Doxorubicin
Correct Answer: Cytarabine (Ara-C)
Q25. Enhanced DNA repair capacity in tumor cells most directly confers resistance to:
- Microtubule inhibitors
- Alkylating agents
- Monoclonal antibodies
- Antimetabolites
Correct Answer: Alkylating agents
Q26. Everolimus is an example of which targeted anticancer class?
- mTOR inhibitor
- Topoisomerase inhibitor
- Alkylating agent
- Antimetabolite
Correct Answer: mTOR inhibitor
Q27. The fluorine atom at C-5 of 5-fluorouracil contributes to its mechanism by:
- Enhancing microtubule binding
- Preventing methylation of uracil after conversion to FdUMP and inhibiting thymidylate synthase
- Increasing alkylation of DNA guanine residues
- Blocking topoisomerase II
Correct Answer: Preventing methylation of uracil after conversion to FdUMP and inhibiting thymidylate synthase
Q28. Hemorrhagic cystitis resulting from acrolein metabolite is most associated with which drug?
- Cyclophosphamide
- Bleomycin
- Doxorubicin
- 5-Fluorouracil
Correct Answer: Cyclophosphamide
Q29. Bleomycin and dactinomycin are classified as which type of antineoplastic agents?
- Antitumor antibiotics
- Antimetabolites
- Alkylating agents
- Monoclonal antibodies
Correct Answer: Antitumor antibiotics
Q30. The most common and clinically significant hematologic toxicity shared by many cytotoxic antineoplastics is:
- Hyperglycemia
- Myelosuppression leading to neutropenia
- Hypertension
- Peripheral neuropathy only
Correct Answer: Myelosuppression leading to neutropenia
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