[Demonstration of BCR-ABL rearrangement in a patient with apparently Ph-negative chronic myeloid leukemia of 15 years' duration].

We have studied the haematologic cytogenetic and molecular features in a patient with Ph negative CML of 15 years of evolution. Cytogenetic analysis showed a normal karyotype in different studies. Molecular study showed rearrangement within bcr region. This gene fusion between c-abl oncogene and bcr gene is typical of the Ph chromosome. These results show the usefulness of performing a molecular study in those patients with Ph negative CML.