Gene copy number alteration profile and its clinical correlation in B-cell acute lymphoblastic leukemia
LEUKEMIA & LYMPHOMA
Authors: Gupta, Sanjeev Kumar; Bakhshi, Sameer; Kumar, Lalit; Kamal, Vineet Kumar; Kumar, Rajive
Abstract
The genes related to B-cell development are frequently altered in B-cell acute lymphoblastic leukemia (B-ALL). One hundred sixty-two newly diagnosed B-ALL cases, median age 8.5 years (2 months-67 years), were prospectively analyzed for copy number alterations (CNAs) in CDKN2A/B, IKZF1, PAX5, RB1, ETV6, BTG1, EBF1, and pseudoautosomal region genes (CRLF2, CSF2RA, IL3RA) using multiplex ligation-dependent probe amplification. The CNAs were detected in 114 (70.4%) cases; most commonly affected genes being CDKN2A/B-55 (34%), PAX5-51 (31.5%), and IKZF1-43 (26.5%). IKZF1 and RB1 deletions correlated with higher induction failure. Patients classified as good-risk, according to the integrated CNA profile and cytogenetic criteria, had lower induction failure [5 (8.6%) vs. 20 (25.3%); p=0.012]. Those classified as good-risk, based on CNA profile irrespective of cytogenetics, also showed lower induction failure [6 (9.4%) vs. 19 (26%); p=0.012]. The CNA profile identified patients with better induction outcome and has a potential role in better risk stratification of B-ALL.
Prognostic gene alterations and clonal changes in childhood B-ALL
LEUKEMIA RESEARCH
Authors: Erbilgin, Yucel; Firtina, Sinem; Mercan, Sevcan; Ng, Ozden Hatirnaz; Karaman, Serap; Tasar, Orcun; Karakas, Zeynep; Celkan, Tulin Tiraje; Zenging, Emine; Sarperg, Nazan; Yildirmak, Zeynep Yildiz; Sisko, Sinem; Ozbek, Ugur; Sayitoglu, Muge
Abstract
Genomic profiles of leukemia patients lead to characterization of variations that provide the molecular classification of risk groups, prediction of clinical outcome and therapeutic decisions. In this study, we examined the diagnostic (n = 77) and relapsed (n = 31) pediatric B-cell acute lymphoblastic leukemia (B-ALL) samples for the most common leukemia-associated gene variations CRLF2, JAK2, PAX5 and IL7R using deep sequencing and copy number alterations (CNAs) (CDKN2A/2B, PAX5, RB1, BTG1, ETV6, CSF2RA, IL3RA and CRLF2) by multiplex ligation proximity assay (MLPA), and evaluated for the clonal changes through relapse. Single nucleotide variations SNVs were detected in 19% of diagnostic 15.3% of relapse samples. The CNAs were detected in 55% of diagnosed patients; most common affected genes were CDKN2A/2B, PAX5, and CRLF2. Relapse samples did not accumulate a greater number of CNAs or SNVs than the cohort of diagnostic samples, but the clonal dynamics showed the accumulation/disappearance of specific gene variations explained the course of relapse. The CDKN2A/2B were most frequently altered in relapse samples and 32% of relapse samples carried at least one CNA. Moreover, CDKN2A/2B alterations and/or JAK2 variations were associated with decreased relapse-free survival. On the other hand, CRLF2 copy number alterations predicted a better survival rate in B-ALL. These findings contribute to the knowledge of CDKN2A/2B and CRLF2 alterations and their prognostic value in B-ALL. The integration of genomic data in clinical practice will enable better stratification of ALL patients and allow deeper understanding of the nature of relapse.