Anticancer Drugs Practice Questions

Q: The provided figure illustrates the mechanism of action of which of the following drugs?

Vinblastine. ***Vinblastine*** - **Binds to tubulin** and prevents **microtubule polymerization**, disrupting the mitotic spindle formation. - Causes **metaphase arrest** by blocking chromosome separation, leading to cancer cell death. *Cisplatin* - Works by forming **DNA cross-links** between and within DNA strands, not by affecting microtubules. - Mechanism involves **alkylation** of DNA bases, particularly guanine, leading to DNA damage and apoptosis. *Imatinib* - Acts as a **tyrosine kinase inhibitor**, specifically targeting **BCR-ABL** fusion protein in chronic myeloid leukemia. - Does not interact with **microtubules** but rather blocks abnormal protein kinase signaling pathways. *Trastuzumab* - A **monoclonal antibody** that targets **HER2 receptors** on breast cancer cells overexpressing this protein. - Works through **antibody-dependent cellular cytotoxicity** and receptor blockade, not microtubule disruption.

Q: Which anticancer drug is known to cause nephrotoxicity?

Cisplatin. **Explanation:** **Cisplatin** is a potent platinum-based alkylating agent used for various solid tumors. Its dose-limiting toxicity is **nephrotoxicity**, specifically causing acute tubular necrosis (ATN) in the proximal convoluted tubules. This occurs because cisplatin accumulates in the renal tubular cells, leading to oxidative stress and apoptosis. To prevent this, patients are managed with **aggressive pre- and post-treatment hydration** and the administration of **Amifostine** (a cytoprotective free-radical scavenger). **Analysis of Incorrect Options:** * **A. Imatinib:** A tyrosine kinase inhibitor (BCR-ABL) used in CML. Its hallmark side effect is **periorbital edema** and fluid retention, not primary nephrotoxicity. * **B. Irinotecan:** A Topoisomerase I inhibitor used in colorectal cancer. Its signature toxicity is **severe diarrhea** (early phase due to cholinergic crisis; late phase due to SN-38 metabolite). * **C. Fosfestrol:** A synthetic estrogen (prodrug of diethylstilbestrol) used in prostate cancer. Common side effects include gynecomastia and thromboembolic complications. **NEET-PG High-Yield Pearls:** * **Cisplatin Toxicities:** Remember the "3 Os": **O**totoxicity (high-frequency hearing loss), **O**liguria (Nephrotoxicity), and severe **O**mesis (highly emetogenic). * **Electrolyte Imbalance:** Cisplatin frequently causes **hypomagnesemia** due to renal wasting. * **Drug of Choice:** While Cisplatin is nephrotoxic, **Carboplatin** (its analog) is more associated with **myelosuppression** (thrombocytopenia) but has significantly less renal and ototoxicity.

Q: Alkylating agents are known to cause which of the following conditions?

Both bladder cancer and acute myelocytic leukemia. **Explanation:** Alkylating agents (e.g., Cyclophosphamide, Busulfan, Melphalan) are cell-cycle non-specific drugs that act by forming covalent bonds with DNA, leading to cross-linking and strand breaks. While they are effective in treating malignancies, they are inherently **mutagenic and carcinogenic** due to their permanent alteration of DNA structure. 1. **Acute Myelocytic Leukemia (AML):** This is a well-documented long-term complication of alkylating agent therapy. These drugs induce chromosomal aberrations (often involving chromosomes 5 and 7) in hematopoietic stem cells. This "therapy-related AML" typically occurs 3–10 years after treatment. 2. **Bladder Cancer:** Specifically associated with **Cyclophosphamide** and **Ifosfamide**. These drugs are metabolized into **Acrolein**, a toxic metabolite that causes hemorrhagic cystitis. Chronic irritation and DNA damage to the urothelium by acrolein significantly increase the risk of transitional cell carcinoma of the bladder. **Analysis of Options:** * **Option A & B:** Both are correct, but incomplete individually. * **Option D:** There is no established causal link between alkylating agents and the development of prostate cancer. **High-Yield Clinical Pearls for NEET-PG:** * **Mesna** (2-Mercaptoethane sulfonate Na) is administered with Cyclophosphamide to neutralize acrolein and prevent hemorrhagic cystitis. * **Busulfan** is notorious for causing **Pulmonary Fibrosis** ("Busulfan lung") and hyperpigmentation. * **Nitrosoureas** (Lomustine, Carmustine) are highly lipid-soluble and are the drugs of choice for **Brain tumors** (Glial tumors). * **Secondary Malignancy:** Alkylating agents are the most common class of anticancer drugs to cause secondary cancers.

Q: All are true regarding selective estrogen receptor downregulator (SERD), Fulvestrant, except?

Is slower, short-acting, and less safe than SERMs.. **Explanation** **Fulvestrant** is a unique hormonal agent classified as a **Selective Estrogen Receptor Downregulator (SERD)** [1]. Unlike SERMs (e.g., Tamoxifen), which have agonist effects in some tissues and antagonist effects in others, Fulvestrant is a **pure estrogen antagonist** with no agonist activity [3]. **Why Option C is the correct (False) statement:** Fulvestrant is actually **longer-acting** and has a **better safety profile** compared to many SERMs. It has a long half-life (approx. 40 days), allowing for infrequent dosing [1]. Furthermore, because it lacks the partial agonist activity of Tamoxifen, it does **not** increase the risk of endometrial cancer or venous thromboembolism, making it safer in those specific regards [2]. **Analysis of other options:** * **Option A:** It is FDA-approved for the treatment of hormone receptor-positive (HR+) **advanced or metastatic breast cancer**, particularly in postmenopausal women who have progressed on other anti-estrogen therapies [3]. * **Option B:** It binds to estrogen receptors (ER) with high affinity, blocking estrogen binding and triggering the **degradation (downregulation)** of the receptor protein [1]. Thus, it acts as a pure antagonist. * **Option D:** Due to its pharmacokinetic profile, it is administered as a **500 mg intramuscular (IM) injection** once monthly (after an initial loading dose) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** "Bind, Block, Degrade." It leads to a total reduction in the number of estrogen receptors in the cell [1]. * **Indication:** Second-line therapy for metastatic breast cancer after Tamoxifen or Aromatase Inhibitor failure [3]. * **Side Effects:** Most common are injection site pain, hot flashes, and nausea. * **Comparison:** Unlike Tamoxifen (SERM), Fulvestrant does **not** carry a risk of uterine (endometrial) hyperplasia [2].

Q: Tretinoin is useful in the treatment of which type of leukemia?

M3. **Explanation:** **Tretinoin (All-Trans Retinoic Acid or ATRA)** is the standard of care for **Acute Promyelocytic Leukemia (APL)**, which is classified as **M3** under the French-American-British (FAB) system. **Why M3 is correct:** APL (M3) is characterized by a specific chromosomal translocation **t(15;17)**. This translocation fuses the Retinoic Acid Receptor alpha (RARα) gene on chromosome 17 with the Promyelocytic Leukemia (PML) gene on chromosome 15. The resulting **PML-RARα fusion protein** blocks myeloid differentiation at the promyelocyte stage. Tretinoin works by binding to this abnormal receptor, inducing the **differentiation** of leukemic promyelocytes into mature neutrophils, thereby inducing remission. **Why other options are incorrect:** * **M2 (Acute Myeloblastic Leukemia with maturation):** Commonly associated with t(8;21). It does not involve the RARα mutation and does not respond to differentiation therapy with ATRA. * **M5 (Acute Monocytic Leukemia):** Characterized by monocytic lineage; often associated with gum hypertrophy and skin involvement. It is treated with standard induction chemotherapy (7+3 regimen). * **M7 (Acute Megakaryoblastic Leukemia):** Associated with Down Syndrome (in children <5 years) and extensive marrow fibrosis. It does not respond to ATRA. **High-Yield Clinical Pearls for NEET-PG:** * **Differentiation Syndrome:** A life-threatening side effect of ATRA characterized by fever, dyspnea, and pulmonary infiltrates. It is managed with **Dexamethasone**. * **DIC Risk:** M3 is highly associated with **Disseminated Intravascular Coagulation (DIC)** due to the release of procoagulants from promyelocyte granules. * **Arsenic Trioxide:** Also used in M3 to degrade the PML-RARα protein, often in combination with ATRA.

Q: A patient was incidentally diagnosed with a lump during a routine health checkup. Following ultrasound and guided biopsy, histopathological examination revealed a diagnosis. The patient was initiated on chemotherapy that included a drug obtained from a specific plant. What is the site of action of this drug?

Tubulin (mitotic inhibitor). ***Tubulin (mitotic inhibitor)*** - Plant-derived chemotherapeutic agents like **vinca alkaloids** (vincristine, vinblastine from *Vinca rosea*) and **taxanes** (paclitaxel from *Taxus brevifolia*) target **tubulin** and disrupt **microtubule** formation. - These drugs prevent proper **mitotic spindle** formation, leading to cell cycle arrest in **M-phase** and subsequent **apoptosis** in rapidly dividing cancer cells. *DNA alkylation* - **Alkylating agents** like **cyclophosphamide** and **nitrogen mustards** form **covalent bonds** with DNA bases, causing cross-linking. - These are not typically plant-derived drugs and work through direct **DNA damage** rather than affecting cellular structures. *Topoisomerase II inhibition* - **Etoposide** and **doxorubicin** inhibit **topoisomerase II**, preventing DNA **supercoiling** and causing DNA breaks. - While some topoisomerase inhibitors are plant-derived, the question specifically hints at drugs affecting **cellular division machinery** rather than DNA enzymes. *DNA intercalation* - **Intercalating agents** like **actinomycin D** insert between **DNA base pairs**, distorting the double helix structure. - These drugs primarily affect **transcription** and **replication** processes rather than the **mitotic apparatus** targeted by plant-derived anti-mitotic agents.

Q: Which antineoplastic drug is a peptide?

Bleomycin. **Explanation:** **Bleomycin** is the correct answer because it is a unique glycopeptide antibiotic derived from *Streptomyces verticillus*. Structurally, it consists of a complex of small peptides and sugars. It functions by binding to DNA and chelating ferrous iron ($Fe^{2+}$), leading to the formation of free radicals that cause single- and double-stranded DNA breaks. **Analysis of Options:** * **Bleomycin (Correct):** A peptide-based antineoplastic agent. It is cell-cycle specific, acting primarily in the **G2 phase**. * **Aspartame:** This is an artificial non-saccharide sweetener (a dipeptide of aspartic acid and phenylalanine). It has no antineoplastic properties. * **Valinomycin:** A depsipeptide antibiotic that acts as a potassium ionophore. While it has biological activity, it is not used as a clinical antineoplastic drug. * **Dactinomycin (Actinomycin D):** While it contains peptide loops (pentapeptide lactones), it is primarily classified as a **chromopeptide** or an intercalating antibiotic. In the context of standard pharmacology exams, Bleomycin is the classic example cited as a "peptide" anticancer drug. **High-Yield Clinical Pearls for NEET-PG:** * **Dose-limiting toxicity:** Unlike most anticancer drugs, Bleomycin is **not** significantly myelosuppressive. Its dose-limiting toxicity is **Pulmonary Fibrosis**. * **Metabolism:** It is inactivated by the enzyme *bleomycin hydrolase*, which is deficient in the lungs and skin, explaining its specific organ toxicities (fibrosis and hyperpigmentation/flagellate dermatitis). * **Clinical Use:** It is a key component of the **ABVD** regimen for Hodgkin’s Lymphoma and the **BEP** regimen for Germ Cell Tumors.

Q: Which antineoplastic agent is an antifolate drug?

Methotrexate. **Explanation:** **1. Why Methotrexate is Correct:** Methotrexate is the prototypical **antifolate** antimetabolite. It acts by competitively and irreversibly inhibiting the enzyme **Dihydrofolate Reductase (DHFR)**. This inhibition prevents the conversion of dihydrofolate to tetrahydrofolate (the active form of folic acid), which is essential for the synthesis of thymidylate and purine nucleotides. Consequently, DNA synthesis, repair, and cellular replication are halted, specifically during the **S-phase** of the cell cycle. **2. Why the Other Options are Incorrect:** * **Adriamycin (Doxorubicin):** An **Anthracycline antibiotic** that works by intercalating between DNA base pairs, inhibiting Topoisomerase II, and generating free radicals. * **Vincristine:** A **Vinca alkaloid** that acts as a mitotic inhibitor. It binds to tubulin and prevents the polymerization of microtubules, leading to **M-phase** arrest. * **Cyclophosphamide:** An **Alkylating agent** (Nitrogen mustard) that forms cross-links within DNA strands, preventing DNA replication. It is a prodrug activated by hepatic CYP450. **Clinical Pearls for NEET-PG:** * **Rescue Therapy:** High-dose Methotrexate toxicity is managed with **Leucovorin (Folinic acid)**, which bypasses the blocked DHFR enzyme to provide a source of active folate. * **Adverse Effects:** Notable for causing mucositis, myelosuppression, and hepatotoxicity. Chronic use can lead to hepatic fibrosis. * **Antidote:** **Glucarpidase** can be used to rapidly lower extracellular methotrexate levels in patients with renal failure. * **Other Antifolates:** Pemetrexed (used in Mesothelioma) and Pralatrexate.

Q: Which of the following statements is true about imatinib?

All of the above.. **Explanation:** Imatinib is a revolutionary targeted therapy that belongs to the class of **Tyrosine Kinase Inhibitors (TKIs)**. It works by competitively binding to the ATP-binding site of specific tyrosine kinases, preventing the phosphorylation of substrates and subsequent cell signaling. * **Mechanism of Action (Option A):** Imatinib specifically inhibits the **BCR-ABL** tyrosine kinase (the product of the Philadelphia chromosome), as well as **c-KIT** (CD117) and **PDGFR** (Platelet-Derived Growth Factor Receptor). * **Clinical Utility (Option B):** Due to its inhibition of c-KIT, it is the first-line treatment for **Gastrointestinal Stromal Tumors (GIST)**. It is also the gold standard for **Chronic Myeloid Leukemia (CML)**. * **Side Effect Profile (Option C):** A hallmark side effect of imatinib is **fluid retention**, which most commonly manifests as **periorbital edema** and **pedal edema**. Other side effects include nausea, muscle cramps, and diarrhea. Since all three statements are pharmacologically accurate, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **The "Magic Bullet":** Imatinib was the first drug designed to target a specific molecular abnormality (BCR-ABL). * **Resistance:** Resistance to imatinib often occurs due to mutations in the BCR-ABL kinase domain (e.g., **T315I mutation**). In such cases, second-generation TKIs like **Dasatinib** or **Nilotinib** are used. * **Monitoring:** Patients on imatinib should be monitored for cardiac function and fluid status.

Question 1

The provided figure illustrates the mechanism of action of which of the following drugs?

Accepted Answer

Vinblastine

Answer

Cisplatin

Answer

Imatinib

Answer

Trastuzumab

Question 2

Cetuximab (an EGFR antagonist) can be used in which of the following conditions?

Accepted Answer

Palliation in head and neck cancer

Answer

Anal canal carcinoma

Answer

Gastric carcinoma

Answer

Lung carcinoma

Question 3

Which anticancer drug is known to cause nephrotoxicity?

Accepted Answer

Cisplatin

Answer

Imitanib

Answer

Irinotecan

Answer

Fosfestrol

Question 4

Alkylating agents are known to cause which of the following conditions?

Accepted Answer

Both bladder cancer and acute myelocytic leukemia

Answer

Bladder cancer

Answer

Acute myelocytic leukemia

Answer

Prostate cancer

Question 5

All are true regarding selective estrogen receptor downregulator (SERD), Fulvestrant, except?

Accepted Answer

Is slower, short-acting, and less safe than SERMs.

Answer

Used for the treatment of advanced breast cancer.

Answer

Is a selective estrogen antagonist.

Answer

Administered as a once-monthly intramuscular dose.

Question 6

Tretinoin is useful in the treatment of which type of leukemia?

Accepted Answer

M3

Answer

M2

Answer

M5

Answer

M7

Question 7

A patient was incidentally diagnosed with a lump during a routine health checkup. Following ultrasound and guided biopsy, histopathological examination revealed a diagnosis. The patient was initiated on chemotherapy that included a drug obtained from a specific plant. What is the site of action of this drug?

Accepted Answer

Tubulin (mitotic inhibitor)

Answer

DNA alkylation

Answer

Topoisomerase II inhibition

Answer

DNA intercalation

Question 8

Which antineoplastic drug is a peptide?

Accepted Answer

Bleomycin

Answer

Aspartame

Answer

Valinomycin

Answer

Dactinomycin

Question 9

Which antineoplastic agent is an antifolate drug?

Accepted Answer

Methotrexate

Answer

Adriamycin

Answer

Vincristine

Answer

Cyclophosphamide

Question 10

Which of the following statements is true about imatinib?

Accepted Answer

All of the above.

Answer

It acts by inhibition of tyrosine kinase.

Answer

It is used to treat gastrointestinal stromal tumors (GIST).

Answer

A side effect of imatinib is pedal edema.

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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