Acute lymphoblastic leukemia (ALL) is the most common type of blood cancer in children. Studies of patients with ALL report that a total of 40 % of patients with B cell ALL (B-ALL) have changes in genes copy number, translocations, or nucleotide changes in genes encoding principal regulators of B lymphocyte development and differentiation. The most frequent target is the PAX5 gene, which is altered in more than 30 % of patients. We analysed the malignant cells of 68 children and adolescents with B-ALL who were treated at the Clinical Department of the Pediatric Hematology and Oncology of the Division of Pediatrics, University Medical Centre Ljubljana between 2012 and 2019, using a method called Sanger sequencing and Multiplex ligation-dependent probe amplification (MLPA). A change in the PAX5 gene was identified in 34 % (23) of patients, more precisely 31 % (21) had an altered PAX5 gene copy number, and 7 % (5) had a pathogenic nucleotide change. Three identified changes have not been described so far: c.1045_1048delCCTC (p.Pro349Serfs), c.101C>T (p.Pro34Leu) and c.197G>A (p.Ser66Asn). We have shown that our results are comparable to the results of major research from foreign studies. The MLPA method is an appropriate tool for detecting deletions and duplications of the PAX5 gene in the diagnosis of patients with B-ALL. Nucleotide changes in the PAX5 gene are less common than copy number variants.
|