Molecular diversity in AML1/ETO fusion transcripts in patients with t(8;21) positive acute myeloid leukaemia.

Patients with acute myeloid leukaemia with maturation (AML-M2) that carried the t(8;21) were tested for the presence of chimeric AML1/ETO mRNA. After RT-PCR, an expected band of 208 bp was observed on gel, as well as some slower migrating bands. The base composition of one of the additional products was determined and was found to contain a new 68-bp ETO sequence present at the fusion of AML1 and ETO genes. The derived protein sequence results in a truncated AML1 gene still containing the putative DNA binding domain. Molecular diversity in the AML1-ETO transcripts will have consequences for the detection of minimal residual disease and antisense studies.