Detection of minimal residual disease in a patient with acute myeloid leukemia and t(6;9) at the time of peripheral blood stem cell transplantation.

A 16-year-old Japanese woman with acute myelogenous leukemia (AML) and t(6;9) received peripheral blood stem cell transplantation (PBSCT). Although chromosomal studies just prior to and following PBSCT showed a normal karyotype, reverse transcription-polymerase chain reaction (RT-PCR) detected the mRNA derived from the dek-can fusion gene of t(6;9) following PBSCT and in the harvested stem cells. Following PBSCT, she relapsed. To our knowledge, this case is the first report from Japan in which minimal residual disease was detected with RT-PCR in AML with t(6;9). These methods should improve the use and outcome of PBSCT.