Cytogenetic Profile of Moroccan Pediatric Acute Lymphoblastic Leukemia: Analysis of 155 Cases With a Review of the Literature

The purpose of the present study was to define the frequency of chromosomal abnormalities in 155 Moroccan patients with acute lymphoblastic leukemia referred to the BIOLAB Laboratory from the Children's Hospital of Rabat and compare our findings with those from reported studies. We identified chromosomal aberrations in 66% of the cases, of which 70% revealed recurrent abnormalities with high prognostic value that correlated with the reported data and their lineage. Background: Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, with a peak incidence at 2 to 3 years of age and accounting for almost 30% of all cancers in this age group. It is well established that the identification of cytogenetic abnormalities is highly relevant for the prognosis of and therapeutic decisions in ALL. The purpose of the present study was to define the frequency of recurrent chromosomal abnormalities of ALL in Moroccan patients referred exclusively to the BIOLAB Laboratory of the Children's Hospital of Rabat during a 4-year period and compare our findings to the reported data. Patients and Methods: We performed conventional karyotyping of 155 ALL cases, with a successful cell culture rate of 94%. Results: We identified chromosomal abnormalities in 66% of the total studied cases, of which 70% revealed important recurrent abnormalities with high prognostic value, such as hyperdiploidy, hypodiploidy, t(9;22), t(8;14), t(1;19), and MLL rearrangements. In total agreement with the reported data, most of the patients (56%) in the present study were aged 1 to 5 years, with a male predominance, and B-ALL was the most common blast phenotype (85%). Conclusion: The frequency of most chromosomal rearrangements successfully identified in our study and their lineage correlated with those reported in the published data.