The relative abundances of specific RNA sequences can be used to classify the myeloid leukaemias

The relative concentrations of pCG14 RNA (a myelocyte-specific mRNA), pAM6 RNA (a monocyte-lineage specific marker), and c-myc RNA (present at higher concentrations in more primitive cells) were measured in the RNAs from peripheral blood leucocytes from leukaemic samples and normal individuals. The potential of differences in the relative abundances of these three RNAs in a series of 34 leukaemias was assessed as a means of distinguishing among the myeloid leukaemias. The chronic phase CGL samples were clustered with a high pCG14 RNA, a medium to low c-myc RNA abundance, and a variable pAM6 RNA level. The ANLL samples could be distinguished from the chronic phase CGL by virtue of different relative abundances of these RNAs: low pCG14, medium to high c-myc and a variable pAM6. The acute phase CGL samples showed a variety of relative RNA abundances with some samples sited within the ANLL region. Using samples obtained during the progression of CGL we have shown a shift in the relative abundances of these RNAs from the CGL region towards the ANLL region, and have suggested that the use of these parameters may allow the progression to acute phase to be monitored and, possibly, predicted.