<prompt> A 56-year-old woman with a history of breast cancer that was treated 5 years ago with lumpectomy and radiation but with no chemotherapy returns with bone pain, fatigue, and weakness. A complete blood count reveals severe anemia, as well as decreased white blood cells and platelets. Examination of a peripheral blood smear reveals small numbers of nucleated red cells, as well as an occasional blast cell and myelocyte. A likely cause of the hematologic abnormalities ischloramphenicol.Diphyllobothrium latum infestation.megaloblastic anemia.myelophthisic anemia.  <response>: - Infiltration of tumor cells from cancers, those of breast prostate - displaces bone marrow elements, thereby causing myelophthisic anemia. OTHER OPTIONS: - Chloramphenicol causes aplastic anemia in some individuals. - Diphyllobothrium latum infestation can result in megaloblastic anemia due to vitamin B12 deficiency. 