Final answer:
Methotrexate and Busulfan are medications that have cumulative doses associated with secondary leukemias.
Correct option is 1 and 2.
Step-by-step explanation:
Methotrexate and Busulfan are medications that have cumulative doses associated with secondary leukemias.
Methotrexate is an antifolate drug that is commonly used in cancer chemotherapy. It works by inhibiting the enzyme dihydrofolate reductase, which is involved in the synthesis of DNA. However, high cumulative doses of methotrexate can damage the DNA and lead to the development of secondary leukemias.
Busulfan is an alkylating agent that is used in the treatment of certain types of cancer, including leukemia. It works by interfering with the DNA in cancer cells, but it can also damage the DNA in normal cells, leading to the development of secondary leukemias.