Final answer:
The malignant disease involving WBC precursors in the bone marrow is called leukemia, a type of blood cancer resulting in the overproduction of leukocytes that do not function properly.
Step-by-step explanation:
The malignant disease involving white blood cell (WBC) precursors in the bone marrow is called leukemia. Leukemia is a type of blood cancer characterized by an abnormal proliferation of white blood cells, either from the myeloid or lymphoid line, resulting in a large number of leukocytes. These cells can be immature, as in acute leukemia, or mature, as in chronic leukemia, but they generally do not function properly, leading to an impaired immune system and other complications.
Lymphoma, on the other hand, involves masses of malignant lymphocytes within lymph nodes and other tissues, and does not originate from WBC precursors in the bone marrow like leukemia does. Multiple myeloma and Hodgkin's disease are other types of blood cancers, but they are not the ones specifically associated with WBC precursors in the bone marrow.