Project description:Philadelphia-like B-cell precursor acute lymphoblastic leukemia (Ph-like ALL) is characterized by distinct genetic alterations and inferior prognosis in children and younger adults. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults. Among 207 adult B-cell precursor ALL patients, 26 (13%) were classified as Ph-like using Affymetrix microarrays. The incidence of this subtype was 25% among 105 B-cell precursor ALL patients negative for BCR-ABL1 and MLL-translocations (B-other). All patients with IgH-CRLF2 translocation (38% vs 0%; p=0.002) or mutations in JAK2 (44% vs. 0%; p<0.001) were exclusively found in the Ph-like subgroup. Clinical and outcome analyses were restricted to patients treated within GMALL trials 06/99 and 07/03 (n=107). The complete remission (CR) rate after induction was 100% for Ph-like (n=19) and B-other patients (n=40). After induction, significantly fewer Ph-like patients reached molecular CR (33% vs 79%; p=0.01). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous CR (24% vs 62%; p<0.001) and overall survival (22% vs 64%; p=0.006) compared to B-other ALL patients. Subsequent analysis led to a clinically applicable algorithm identifying this patient subset with a specificity of 100%. Our study is the first to demonstrate that the profile of genetic events in adult Ph-like ALL resembles pediatric Ph-like ALL and differs from B-other ALL. The Ph-like phenotype associates with inferior outcomes in intensively treated adult ALL patients. Ph-like adult ALL should be recognized as a distinct, high-risk entity and further research on improved diagnostic and therapeutic approaches is needed.
Project description:Philadelphia-like B-cell precursor acute lymphoblastic leukemia (Ph-like ALL) is characterized by distinct genetic alterations and inferior prognosis in children and younger adults. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults. Among 207 adult B-cell precursor ALL patients, 26 (13%) were classified as Ph-like using Affymetrix microarrays. The incidence of this subtype was 25% among 105 B-cell precursor ALL patients negative for BCR-ABL1 and MLL-translocations (B-other). All patients with IgH-CRLF2 translocation (38% vs 0%; p=0.002) or mutations in JAK2 (44% vs. 0%; p<0.001) were exclusively found in the Ph-like subgroup. Clinical and outcome analyses were restricted to patients treated within GMALL trials 06/99 and 07/03 (n=107). The complete remission (CR) rate after induction was 100% for Ph-like (n=19) and B-other patients (n=40). After induction, significantly fewer Ph-like patients reached molecular CR (33% vs 79%; p=0.01). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous CR (24% vs 62%; p<0.001) and overall survival (22% vs 64%; p=0.006) compared to B-other ALL patients. Subsequent analysis led to a clinically applicable algorithm identifying this patient subset with a specificity of 100%. Our study is the first to demonstrate that the profile of genetic events in adult Ph-like ALL resembles pediatric Ph-like ALL and differs from B-other ALL. The Ph-like phenotype associates with inferior outcomes in intensively treated adult ALL patients. Ph-like adult ALL should be recognized as a distinct, high-risk entity and further research on improved diagnostic and therapeutic approaches is needed.
Project description:Philadelphia-like B-cell precursor acute lymphoblastic leukemia (Ph-like ALL) is characterized by distinct genetic alterations and inferior prognosis in children and younger adults. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults. Among 207 adult B-cell precursor ALL patients, 26 (13%) were classified as Ph-like using Affymetrix microarrays. The incidence of this subtype was 25% among 105 B-cell precursor ALL patients negative for BCR-ABL1 and MLL-translocations (B-other). All patients with IgH-CRLF2 translocation (38% vs 0%; p=0.002) or mutations in JAK2 (44% vs. 0%; p<0.001) were exclusively found in the Ph-like subgroup. Clinical and outcome analyses were restricted to patients treated within GMALL trials 06/99 and 07/03 (n=107). The complete remission (CR) rate after induction was 100% for Ph-like (n=19) and B-other patients (n=40). After induction, significantly fewer Ph-like patients reached molecular CR (33% vs 79%; p=0.01). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous CR (24% vs 62%; p<0.001) and overall survival (22% vs 64%; p=0.006) compared to B-other ALL patients. Subsequent analysis led to a clinically applicable algorithm identifying this patient subset with a specificity of 100%. Our study is the first to demonstrate that the profile of genetic events in adult Ph-like ALL resembles pediatric Ph-like ALL and differs from B-other ALL. The Ph-like phenotype associates with inferior outcomes in intensively treated adult ALL patients. Ph-like adult ALL should be recognized as a distinct, high-risk entity and further research on improved diagnostic and therapeutic approaches is needed.
Project description:Background: BCR-ABL1-like, or Ph-like acute lymphoblastic leukemia is characterized by a gene expression profile similar to BCR-ABL1 positive ALL, genetic alterations of lymphoid transcription factor genes, and poor outcome. Sequencing of small numbers of Ph-like ALL cases has identified genetic alterations activating kinase signaling suggesting Ph-like ALL may be amenable to treatment with tyrosine kinase inhibitors. However, the spectrum of genetic alterations in childhood and adult Ph-like ALL is incompletely understood. Methods: We performed genomic profiling of 1736 B-ALL cases and next-generation sequencing for 160 Ph-like cases. We examined the functional effects of chimeric fusion proteins in mouse cell lines. Results: The frequency of Ph-like ALL rose from 11% in children to 26% in young adults, and was associated with very poor outcome. Kinase-activating alterations were identified in 90% of Ph-like cases, most commonly fusions involving 10 kinase or cytokine receptor genes (ABL1, ABL2, CRLF2, CSF1R, EPOR, JAK2, NTRK3, PDGFRB, PTK2B and TYK2), and mutations involving FLT3, IL7R and SH2B3. Expression of ABL1, ABL2, CSF1R and JAK2 fusions resulted in cytokine-independent proliferation of cell lines and activation of pSTAT5. Cells expressing ABL1, ABL2, CSF1R and PDGFRB fusions were sensitive to dasatinib, and JAK2 fusions to ruxolitinib. Conclusions: Ph-like ALL is characterized by a diverse range of genomic alterations that converge on a limited number of kinase signaling pathways amenable to inhibition with currently available tyrosine kinase inhibitors. Trials identifying Ph-like ALL and testing the efficacy of tyrosine kinase inhibitor therapy are warranted
Project description:The Philadelphia chromosome (Ph) encoding the oncogenic BCR-ABL1 kinase defines a subset of ALL with a particularly unfavorable prognosis. Acute lymphoblastic leukemia (ALL) cells are derived from B cell precursors in most cases and typically carry rearranged immunglobulin heavy chain (IGH) variable (V) region genes devoid of somatic mutations. Somatic hypermutation is restricted to mature germinal center B cells and depends on activation-induced cytidine deaminase (AID). Studying AID expression in 108 cases of ALL, we detected AID mRNA in 24 of 28 Ph-positive ALLs as compared to 6 of 80 Ph-negative ALLs. Forced expression of BCR-ABL1 in Ph-negative ALL cells and inhibition of the BCR-ABL1-kinase showed that aberrant expression of AID depends on BCR-ABL1 kinase activity. Consistent with aberrant AID expression in Ph-positive ALL, IGH V region genes and BCL6 were mutated in many Ph-positive but unmutated in most Ph-negative cases. In addition, AID introduced DNA-single-strand breaks within the tumor suppressor gene CDKN2B in Ph-positive ALL cells, which was sensitive to BCR-ABL1 kinase inhibition and silencing of AID expression by RNA interference. These findings identify AID as a BCR-ABL1-induced mutator in Ph-positive ALL cells, which may be relevant with respect to the particularly unfavorable prognosis of this leukemia subset. Keywords: gene expression array-based (RNA / in situ oligonucleotide)
Project description:The Philadelphia chromosome (Ph) encoding the oncogenic BCR-ABL1 kinase defines a subset of ALL with a particularly unfavorable prognosis. Acute lymphoblastic leukemia (ALL) cells are derived from B cell precursors in most cases and typically carry rearranged immunglobulin heavy chain (IGH) variable (V) region genes devoid of somatic mutations. Somatic hypermutation is restricted to mature germinal center B cells and depends on activation-induced cytidine deaminase (AID). Studying AID expression in 108 cases of ALL, we detected AID mRNA in 24 of 28 Ph-positive ALLs as compared to 6 of 80 Ph-negative ALLs. Forced expression of BCR-ABL1 in Ph-negative ALL cells and inhibition of the BCR-ABL1-kinase showed that aberrant expression of AID depends on BCR-ABL1 kinase activity. Consistent with aberrant AID expression in Ph-positive ALL, IGH V region genes and BCL6 were mutated in many Ph-positive but unmutated in most Ph-negative cases. In addition, AID introduced DNA-single-strand breaks within the tumor suppressor gene CDKN2B in Ph-positive ALL cells, which was sensitive to BCR-ABL1 kinase inhibition and silencing of AID expression by RNA interference. These findings identify AID as a BCR-ABL1-induced mutator in Ph-positive ALL cells, which may be relevant with respect to the particularly unfavorable prognosis of this leukemia subset. Experiment Overall Design: To study the gene expression profile of two Ph-positive ALL cell lines (BV173 and SUP-B15) in the presence or absence of 10 μmol/l STI571 for 16 hours
Project description:Gene Expression Classifiers for Minimal Residual Disease and Relapse Free Survival Improve Outcome Prediction and Risk Classification in Children with High Risk Acute Lymphoblastic Leukemia: A Children's Oncology Group Study willm-00140 Assay Type: Gene Expression Provider: Affymetrix Array Designs: HG-U133_Plus_2 Organism: Homo sapiens (ncbitax) Tissue Sites: Blood, Bone marrow Material Types: Peripheral Blood, Bone Marrow Disease States: Childhood Precursor B-Lymphoblastic Leukemia