Outcome of adolescents and young adults with acute lymphoblastic leukemia in a single center in Brazil

ABSTRACT Introduction: Acute lymphoblastic leukemia (ALL) presents a poor prognosis in adults. The adoption of pediatric protocols has been changing this scenario, especially for adolescents and young adults (AYA). Objective and method: We aimed to evaluate a consecutive series of patients treated at the State Institute of Hematology of Rio de Janeiro between 2012 and 2020, focusing on the AYA subgroup. Result: The B-ALL was the most frequent subtype (81.6%) and AYA, the predominant age group (57.7%). The median overall survival (OS) was 9.4 months. High early mortality was observed and sepsis was the main cause of death. Better OS results were noted in AYA, in comparison to over 39y (13.3 × 6.2 months, respectively), the Berlin-Frankfurt-Münster (BFM) being the protocol of choice in this group. Conclusion: The use of the pediatric protocol seems to improve the OS of AYA, however, high rates of deaths from infection were observed, demonstrating the need for advances in the Brazilian public system clinical support.

Outcome of adolescents and young adults with acute lymphoblastic leukemia in a single center in Brazil.

INTRODUCTION: Acute lymphoblastic leukemia (ALL) presents a poor prognosis in adults. The adoption of pediatric protocols has been changing this scenario, especially for adolescents and young adults (AYA). OBJECTIVE AND METHOD: We aimed to evaluate a consecutive series of patients treated at the State Institute of Hematology of Rio de Janeiro between 2012 and 2020, focusing on the AYA subgroup. RESULT: The B-ALL was the most frequent subtype (81.6%) and AYA, the predominant age group (57.7%). The median overall survival (OS) was 9.4 months. High early mortality was observed and sepsis was the main cause of death. Better OS results were noted in AYA, in comparison to over 39y (13.3 × 6.2 months, respectively), the Berlin-Frankfurt-Münster (BFM) being the protocol of choice in this group. CONCLUSION: The use of the pediatric protocol seems to improve the OS of AYA, however, high rates of deaths from infection were observed, demonstrating the need for advances in the Brazilian public system clinical support.

IKZF1 deletions associate with CRLF2 overexpression leading to a poor prognosis in B-cell precursor acute lymphoblastic leukaemia.

Cytokine Receptor-Like Factor 2 (CRLF2) overexpression occurs in 5-15% of B-cell precursor acute lymphoblastic leukaemia (B-ALL). In ∼50% of these cases, the mechanisms underlying this dysregulation are unknown. IKAROS Family Zinc Finger 1 (IKZF1) is a possible candidate to play a role in this dysregulation since it binds to the CRLF2 promoter region and suppresses its expression. We hypothesised that IKZF1 loss of function, caused by deletions or its short isoforms expression, could be associated with CRLF2 overexpression in B-ALL. A total of 131 paediatric and adult patients and 7 B-ALL cell lines were analysed to investigate the presence of IKZF1 deletions and its splicing isoforms expression levels, the presence of CRLF2 rearrangements or mutations, CRLF2 expression and JAK2 mutations. Overall survival analyses were performed according to the CRLF2 and IKZF1 subgroups. Our analyses showed that 25.2% of patients exhibited CRLF2 overexpression (CRLF2-high). CRLF2-high was associated with the presence of IKZF1 deletions (IKZF1del, p = 0.001), particularly with those resulting in dominant-negative isoforms (p = 0.006). Moreover, CRLF2 expression was higher in paediatric samples with high loads of the short isoform IK4 (p = 0.011). It was also associated with the occurrence of the IKZF1 plus subgroup (p = 0.004). Furthermore, patients with CRLF2-high/IKZF1del had a poorer prognosis in the RELLA05 protocol (p = 0.067, 36.1 months, 95%CI 0.0-85.9) and adult cohort (p = 0.094, 29.7 months, 95%CI 11.8-47.5). In this study, we show that IKZF1 status is associated with CRLF2-high and dismal outcomes in B-ALL patients regardless of age.

CRLF2 expression associates with ICN1 stabilization in T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematopoietic malignancy with few molecular alterations showing a consensual prognostic value. CRLF2 overexpression was recently identified in high-risk T-ALL patients. For these cases, no genomic abnormality was found to be associated with CRLF2 overexpression. IKZF1 has been recently shown to be a direct transcriptional regulator of CRLF2 expression. Moreover, it is known that NOTCH1 antagonizes IKZF1 in T-ALL. In light of these pieces of evidence, we reasoned that IKZF1 binding perturbation and CRLF2 upregulation could be associated in T-ALL. We evaluated two independent series of pediatric T-ALL cases (PHOP, n = 57 and TARGET, n = 264) for the presence of common T-ALL molecular abnormalities, such as NOTCH1/FBXW7 mutations. We also assessed CRLF2 and IKZF1 gene expression. CRLF2 overexpression was observed in 14% (PHOP) and 16% (TARGET) of T-ALL patients. No correlation was found between mRNA expression of CRLF2 and IKZF1 in both cohorts. Interestingly, we show that patients with mutations affecting NOTCH1-PEST domain and/or FBXW7 had higher CRLF2 expression (P = .04). In summary, we demonstrate for the first time that only mutations resulting in ICN1 (intracellular domain of NOTCH1) stabilization are associated with CRLF2 overexpression.