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

Cytogenetic abnormalities and TP53 and RAS gene profiles of childhood acute lymphoblastic leukemia in Morocco

BACKGROUND

Recurrent genetic abnormalities affecting pivotal signaling pathways are the hallmark of childhood acute lymphoblastic leukemia (ALL). The identification of these aberrations remains clinically important. Therefore, we sought to determine the cytogenetic profile and the mutational status of TP53 and RAS genes among Moroccan childhood cases of ALL.

METHODS

In total, 35 patients with childhood ALL were enrolled in the study. The diagnosis and treatment were established in the Pediatric Hematology and Oncology Center at the Children's Hospital of Rabat. Chromosome banding analysis and fluorescence in situ hybridization were used to detect genetic aberrations. Blood samples were screened for TP53 and RAS mutations using Sanger sequencing.

RESULTS

Of the 35 cases, 30 were B-lineage ALL (85.7 %). Moreover, a male predominance was observed. Cytogenetic analysis revealed chromosomal anomalies in 27 cases (77.1 %). The most frequent aberrations were high hyperdiploidy and BCR/ABL rearrangement. Interestingly, we found the rare t(15;16) and the t(8;14), which are uncommon translocations in pediatric B-ALL. The mutational analysis revealed Pro72Arg (rs1042522:C > G) and Arg213Arg (rs1800372:A > G) in TP53. In correlation with cytogenetic data, rs1042522:C > G showed a significant association with the occurrence of chromosomal translocations (p = 0.04). However, no variant was detected in NRAS and KRAS genes.

CONCLUSION

Our findings emphasize the significance of detecting chromosomal abnormalities as relevant prognostic markers. We also suggest a low occurrence of genetic variants among Moroccan children with ALL.

Association of TP53 gene polymorphisms with the risk of acute lymphoblastic leukemia in Moroccan children

BACKGROUND

TP53 gene plays a pivotal role in maintaining genetic stability and prevention of malignancies. Alterations of this gene are implicated in more than half of human cancers. To the best of our knowledge, this study is the first to explore TP53 polymorphisms in Moroccan childhood acute lymphoblastic leukemia (ALL).

METHODS AND RESULTS

DNA samples of 45 ALL children were obtained from peripheral blood. A total of 333 healthy Moroccans were used as controls. Polymerase chain reaction and Sanger sequencing were performed to analyze TP53 hotspot exons in cases. We identified a significant protective effect of the TP53-Arg variant at rs1042522 [OR 0.4593 (0.249-0.8472), p = 0.0127] and the Pro/Arg genotype [OR 0.0350 (0.0047-0.2583), p = 0.0010]. Additionally, we found a novel association between the C-allele of Arg213Arg 1800372 [OR 2.7736 (1.3821-5.5664), p = 0.0041] and the risk of childhood ALL. Importantly, TC/CC genotypes of this polymorphism were revealed to enhance the risk of ALL among females [OR 9.0 (3.1555-25.6693), p < 0.0001]. Arg213Arg was also noticed to be associated with the hemoglobin count of patients at diagnosis by linear regression (p = 0.0318). The analysis of penetrance showed a significant association of the CG/GG genotypes at rs1042522 and TC/CC genotypes at rs1800372 to childhood ALL via dominant model [OR 0.2090 (0.09074-0.4814), p = 0.0002 and OR 3.4205 (1.6084-7.2742), p = 0.0014 for rs1042522 and rs1800372 respectively]. No association was found between TP53 polymorphisms and patients survival.

CONCLUSION

Altogether, our findings indicated that TP53 polymorphisms are significantly involved in the genetic susceptibility to childhood ALL in Morocco.

Observation of the molecular genetics among children with acute lymphoblastic leukemia: A retrospective study based on the SEER database

Acute lymphoblastic leukemia (ALL) is one of the most common malignancies of the hematologic system in children. Typically, ALL children with various genetic changes show different incidences, development, and prognoses. This study aimed to analyze the incidence of molecular genetic subtype among ALL children based on their clinical information, and to further investigate the relationship of genetic varieties with the prognostic factors.From 2010 to 2016, a total of 888 ALL children with TEL-AML1 fusion gene, hyperdiploidy, hypodiloidy, IL3-IGH rearranged, E2A PBX1 fusion gene, BCR-ABL1 fusion gene, or mixed lineage leukemia (MML) rearranged were selected and analyzed through the Surveillance, Epidemiology, and End Results database.Our results suggested that, ALL children who lived in the Northern Plains were more likely to experience genetic varieties. In addition, the TEL-AML1 fusion gene, hyperdiploidy, and hypodiloidy were more likely to be detected in ALL children aged 1 to 9 years, while MLL rearrangement was probably detected among ALL children aged <1 year. On the other hand, the 5-year overall survival varied depending on different regions (East: 42.21%; Alaska: 0.001%; Northern Plains: 1.8%; Pacific Coast: 16.3%; and Southwest: 8%), races (African American: 44.5%; white: 18.2%; and Other: 16.3%), and genetic features (TEL-AML1: 10.1%; hyperdiploidy: 19.4%; hypodiloidy: 64.7%; IL3-IGH: 0.01%; E2A PBX1: 14.2%; BCR-ABL1: 15.2%; MLL rearranged: 12.3%).In conclusion, our study found that genetic varieties among ALL children were closely related to their prognoses, and the detection rate of genetic molecules was associated with the age, race, and living area of children.

Clinical Impact of CD25/CD123 Coexpression in Adult B-Cell Acute Lymphoblastic Leukemia Patients

This study aimed to determine the clinical impact of CD25⁺/CD123⁺ coexpression in adult B-cell acute lymphoblastic leukemia (B-ALL) cases. One hundred and twenty newly diagnosed B-ALL patients (≤60 years old) were included in this study. CD123 and CD25 expression on leukemic blast cells were assessed using flow cytometry. CD25⁺/CD123⁺ coexpression was detected in 40/120 B-ALL patients (33.3%). All B-ALL patients showed CD25⁺/CD123⁺ coexpression had lower induction of remission response and shorter overall survival as compared to B-ALL cases lacking coexpression. In conclusion, CD25⁺/CD123⁺ positive coexpression is a reliable flow cytometry marker for prediction of the outcome of adult B-ALL patients and could be used as a novel parameter for risk stratification of adult B-ALL cases.