Detection of a b3a3 type chimera in chronic myeloid leukemia by double hybridisation of RT-PCR products

The standard RT-PCR method performed on RNA of a chronic myeloid leukemia patient resulted in a product of unusual size. Hybridisation to a probe containing the a2 sequences yielded a very faint band. Rehybridisation of the same blot to b3 sequences has given a firm signal. Based on the size of the product and on results of hybridisation tests, a translocation, resulting in a b3a3 juxtaposition, was supposed. The direct sequencing of the RT-PCR product has proven this hypothesis. We concluded, that double hybridisation of RT-PCR products of standard methods is a useful tool in detection of rare bcr-abl chimeras.