Multiplex PCR - a rapid screening method for detection of gene rearrangements in childhood acute lymphoblastic leukemia

Chromosomal rearrangements in childhood acute lymphoblastic leukemia (ALL) play an important role in the identification of clinical relevant subgroups . For rapid and easy detection of the clinically most important gene rearra ngements, a nested multiplex re,verse transcriptase polymerase chain reacti on (multiplex PCR) was developed. This multiplex PCR enables the detection of M-BCR/ABL, m-BCR/ABL, TEL/AML1, and MLL/AF4 fusion transcripts in one PC R reaction. However, the existence of splicing variants and different break points on the DNA level hampers the discrimination of the rearrangements by their fragment size on an agarose gel. Therefore, one of the internal prim ers of each translocation (ABL-2, TEL-2, AF4-2) was labeled with a characte ristic fluorescent dye, and an automatic fluorescence-based DNA fragment an alysis was performed. The sensitivity of this multiplex PCR is in the same range as that of the corresponding single PCR reaction and allows a fast sc reening for the detection of therapy-relevant rearrangements, with a high t urnover of samples.