Minimal residual disease in leukemia: state of the art 1991.

Recent achievements in decreasing the detection level of "minimal residual disease" in leukemia are summarized both in a relevant rat model for acute myelocytic leukemia (BNML) and in the human leukemias. Detection levels as low as 1 leukemic cell per 10(8)-10(9) and 10(5)-10(6) normal bone marrow cells have become realistic in the animal model and in human leukemia, respectively. The implications of these new tools for detecting hidden leukemic cells are discussed.