(A) Flow cytometric analysis of cyCD3 in myeloid/NK cell precursor leukemia cases. The x-axis represents fluorescence intensity (4-decade log scale) and the y-axis the relative cell number. The thick line indicates the histogram for leukemic cells stained with cyCD3 and the thin line indicates the histogram for leukemic cells stained with cyCD22 (negative control). The right shift of the histogram wave observed in patients nos. 2, 3, and 6 indicates that the leukemic cells are cyCD3 dimly positive. In patient no. 2, the fluorescence intensity of 18% of the leukemic cells was calculated to exceed the cut-off level (maximum intensity of negative control), but most (approximately more than 80% to 90%) of them are dimly positive. In patient no. 5, the cyCD22 analysis was not available. (B) CD3ε expression by Northern blotting analysis. HL-60 was used as a negative control and Jurkat was used as a positive control. All six cases expressed CD3ε mRNA to varying extents.