<prompt> The combination of meclorethamine, vincristine, prednisolone, and procarbazine is used for the treatment of patients with:Acute lymphocytic leukemiaChronic lymphocytic leukemiaHodgkins diseaseAcute myelocytic leukemia  <response>: MOPP, the combination regimen of meclorethamine, vincristine Oncovin, prednisone, and procarbazine, is often alternated with the ABVD regimen doxorubicin Adriamycin, bleomycin, vincristine, and dacarbazine in the treatment of patients with Hodgkins disease, These regimens are based on the use of drugs with different mechanisms of action and different toxicities, so that the cancer cells are attacked at different sites of action, and the collective toxicity is not directed toward one organ system. Mechlorethamine is a nitrogen mustard alkylating agent, vincristine is a mitotic spindle poison, prednisone is a glucocoicoid with lymphotoxic effects, and procarbazine has multiple actions directed azainst nucleic acids and proteins. Vincristine and prednisone produce less bone marrow suppression than alkylating agents and antimetabolites. 