Background: The rearrangement of the bcr/abl gene constitutes the molecular substrate of the Philadelphia chromosome (Ph'). The aim of this study was to analyze the usefulness of bcr/abl rearrangement in the diagnosis and evolution of chronic myeloid leukemia (CML).
Methods: The rearrangement of the bcr/abl gene was studied in 81 cases of which 34 corresponded to patients with CML (29 Ph' positive chromosome, 2 Ph' negative chromosome and 3 without karyotype), 2 patients with Ph' positive acute lymphoblastic leukemia, 15 patients with chronic myeloproliferative syndromes different from CML and 30 controls. Of the patients with CML, 6 were reevaluated when a blastic crisis was developed, 2 after receiving interferon treatment and 1 following allogeneic bone marrow transplantation. The technique used was that of Southern blotting using the restriction enzymes Bgl II and BamHI and the transprobe.
Results: Rearrangement of the bcr/abl gene was observed in all the patients with CML except in one with Ph' negative chromosome. In the remaining cases bcr/abl rearrangement was not observed.
Conclusions: The Southern blotting technique for the study of the bcr/abl gene rearrangement is a sensitive and specific method in the diagnosis of chronic myeloid leukemia constituting a valid alternative to chromosomic study when this cannot be carried out or is not conclusive. It may also be used for the control of treatment in chronic myeloid leukemia.