Expression of bcr/abl mRNA in peripheral granulocytes of 4-5-6. The RT-PCR products generated with RT (+RT) or without RT (−RT) were electrophoresed in a 3% agarose gel and stained with ethidium bromide. Products of genomic and mRNA amplification are indicated by arrows. RT-PCR without RNA (No RNA) was also performed as a negative control. The positions of DNA markers are shown on the left.