Aneuploidy identification in pre-B acute lymphoblastic leukemia patients at diagnosis by Multiplex Ligation-dependent...

Three-quarters of the patients with acute lymphoblastic leukemia (ALL), show numerical or structural chromosomal alterations, which are important factors in leukemogenesis. The use of Multiplex Ligation-dependent Probes Amplification (MLPA) has been mainly limited for searching copy number alterations of genes, suggesting that MLPA could detect numerical alterations in cancer. However, the use of MLPA in pediatrics to analyze subtelomeric sequences for aneuploidy detection has not been considered in previous studies. The aim of this study was to identify aneuploidy for the first time using MLPA and correlate the results with karyotype and DNA-index (DI), from preB ALL patients. Forty-two bone marrow samples were analyzed by cytogenetics and flow cytometry to determine the DI. The chromosomal gains and/or losses were detected by the SALSA MLPA P036 Subtelomere Mix 1 probemix^®. The chromosomal number matched in 36 out of 42 samples between MLPA and karyotype (R²=0.7829, p=3.7×10^-10), 18/42 between MLPA and DI (R²=0.1556, p=0.023), and 20/42 between karyotype and DI (R²=0.1509, p=0.015). MLPA results correlated with karyotype and DI. The use of MLPA led us to identify a gained marker chromosome. Our results indicate that MLPA could be a useful and fast alternative tool for aneuploidy identification in pediatric leukemia.