Investigation of TEL/AML1 and BCR/ABL Fusion Genes in Patients Affected by Acute Lymphoblastic Leukaemia Using Interphase in situ Hybridization

A total of sixty patients affected with acute lymphoblastic leukaemia (ALL), including thirty children and thirty adults were studied by the conventional cytogenetics and fluorescence in situ hybridization (FISH) techniques. The TEL, AML1, ABL, and BCR probes were applied on interphase cells prepared from bone marrow samples. The signal distribution and the presence of the fused genes, together with the clinical features were statistically analysed. The age ranged from 16 to 42 years (mean 23±7.3) in adults and 2 to 15 years (mean 6.9±3.9) in children. In children 46% had an abnormal FISH pattern, including 23% having fused ABL/AML1, 3% and 7% with deletion and gain in TEL gene respectively; 3% and 10% having deletion and gain in AML1 gene, respectively. In adults, out of eight (27%) patients had abnormal FISH pattern, of those only 3% presented the fused TEL/AML1 gene, and the distribution of signal patterns was the same as found in children. A direct correlation were also found between the presence of fused TEL/AML1 genes and decreased WBC (P < 0.05), however this was not significant in adults. The adults with more than 50000 WBC had a significantly lower survival period (P < 0.05). Our results indicate that the combination of conventional karyotyping and molecular cytogenetics (FISH), and a long time follow up study could provide clinicians useful information leading more effective therapeutic management for the ALL patients.