[Rearrangement of the alpha RAR and pml genes in promyelocytic leukemia]

The purpose of this work was to assess the re-arrangement of RAR-alpha and pml genes in a group of patients with acute promyelocytic leukaemia (APL) in different stages of the disease. Twenty-two patients with APL were studied. Of them, 17 were at the onset and 5 had achieved already complete haematological remission (CR). Evolutive post-remission studies were performed in 8 cases. The cytogenetic analysis was carried out at diagnosis by means of the G-band technique in 14 patients. The molecular study of RAR-alpha and pml genes was made with the Southern method. The common anomaly, t(15;17) was present in 7 of the 9 cases with evaluable metaphases (78%), in one case a 17q+ was the only cytogenetic alteration and another patient had normal karyotype. The molecular study showed re-arrangement of one or both genes involved in the translocation in the 17 patients studied at the onset of the APL. Those patients studied only in CR showed a germinal configuration. Rearrangement bands reappeared in 3 of the 8 patients evaluated along their clinical course. These results are in concordance with previous studies, in which re-arrangement of RAR-alpha and pml genes had been found in APL, despite there are instances in which no cytogenetic anomalies are found; this confirms the interest of molecular studies in the diagnosis and follow-up of APL patients.