The results in different types of leukaemia were (number of patients with detectable mdr1 RNA/total number of patients; median number of transcripts per cell in samples with detectable mdr1 RNA); de novo untreated acute myelocytic leukaemia (AML): 20/44; 0.7, secondary acute myelocytic leukaemia: 8/13; 1.1, acute lymphocytic (ALL) and undifferentiated leukaemia: 5/14; 0.6, relapsed leukaemia: 7/15; 0.7.