 The leukemia-specific AML1/ETO fusion gene has been shown to be detected by reverse transcriptase polymerase chain reaction (RT-PCR) analysis in patients with t(8;21) acute myelogenous leukemia (AML) in long-term remission.     ///    Persistence of multipotent progenitors expressing AML1/ETO transcripts in long-term remission patients with t(8;21) acute myelogenous leukemia..     ///    "Accordingly, these committed progenitor cells that express AML1/ETO mRNA during remission likely have arisen from common t(8;21)+ pluripotent progenitor cells with at least trilineage differentiation potential. "    ///    "In the present study, the AML1/ETO mRNA could be detected by RT-PCR in bone marrow (BM) and/or peripheral blood (PB) samples from all 18 patients who had been maintaining complete remission for 12 to 150 months (median, 45 months) following chemotherapy or PB stem cell transplantation (PBSCT), whereas it could not be detected in four patients who had been maintaining remission for more than 30 months following allogeneic BM transplantation (BMT). "    ///    We surveyed the expression of AML1/ETO mRNA in clonogenic progenitors from BM in these cases.     ///    The AML1/ETO mRNA+ progenitors showed the PGK allele identical to that detected in the leukemic blasts from the time of initial diagnosis.     ///    "Notably, 51 of 2,469 colonies from clonogenic progenitors (2.1%) expressed the AML1/ETO mRNA in 18 cases who were RT-PCR+ in BM and/or PB samples. "