All of the following anticancer drugs are cell cycle non-specific except?
**Core Concept**
Cell cycle non-specific anticancer drugs can be active in all phases of the cell cycle, whereas cell cycle-specific drugs are active only during specific phases. This distinction is crucial in chemotherapy, as it influences the choice of treatment and potential side effects.
**Why the Correct Answer is Right**
Vincristine is a vinca alkaloid that acts by binding to tubulin, preventing microtubule formation, and thus inhibiting cell division. It is cell cycle-specific, primarily affecting the M phase of the cell cycle, where cells are actively dividing. In contrast, most other anticancer drugs listed are cell cycle non-specific, affecting cells in all phases of the cell cycle.
**Why Each Wrong Option is Incorrect**
**Option A:** Cisplatin is a platinum-based drug that forms platinum-DNA adducts, leading to DNA damage and apoptosis. It is cell cycle non-specific, as it can induce cell death in cells in all phases of the cell cycle.
**Option C:** Mitomycin-C is an alkylating agent that cross-links DNA, causing DNA damage and apoptosis. It is cell cycle non-specific, as it can affect cells in all phases of the cell cycle.
**Option D:** Cyclophosphamide is an alkylating agent that forms DNA cross-links, leading to DNA damage and apoptosis. It is cell cycle non-specific, as it can induce cell death in cells in all phases of the cell cycle.
**Clinical Pearl / High-Yield Fact**
Cell cycle specificity is crucial in chemotherapy, as it determines the potential for myelosuppression, mucositis, and other side effects. For example, cell cycle-specific drugs like vincristine are more likely to cause neurotoxicity, whereas cell cycle non-specific drugs like cisplatin can cause renal toxicity.
**✓ Correct Answer: B. Vincristine**