Final answer:
Chemotherapy drugs that target microtubule dynamics disrupt mitosis by inhibiting microtubule assembly and disassembly, preventing the formation of spindle fibers and hindering cell division.
Step-by-step explanation:
Chemotherapy drugs that target microtubule dynamics, such as vincristine and colchicines, are used in cancer-targeting treatments because they disrupt mitosis by binding to tubulin, the subunit of microtubules. These drugs interfere with microtubule assembly and disassembly, which hinders cell division. By targeting microtubules, the drugs prevent the formation of spindle fibers, which are essential for proper chromosome movement during cell division. As a result, the cancer cells are unable to divide and proliferate, making these drugs effective in inhibiting cancer growth.