Mutational profiling of acute lymphoblastic leukemia with testicular relapse.

Relapsed acute lymphoblastic leukemia (ALL) is the leading cause of deaths of childhood cancer. Although relapse usually happens in the bone marrow, extramedullary relapse occasionally occurs including either the central nervous system or testis (<1-2%). We selected two pediatric ALL patients who experienced testicular relapse and interrogated their leukemic cells with exome sequencing. The sequencing results and clonality analyses suggest that relapse of patient D483 directly evolved from the leukemic clone at diagnosis which survived chemotherapy. In contrast, relapse leukemia cells (both bone marrow and testis) of patient D727 were likely derived from a common ancestral clone, and testicular relapse likely arose independently from the bone marrow relapsed leukemia. Our findings decipher the mutational spectra and shed light on the clonal evolution of two cases of pediatric ALL with testicular relapse. Presence of CREBBP/NT5C2 mutations suggests that a personalized therapeutic approach should be applied to these two patients

Mutational profiling of acute lymphoblastic leukemia with testicular relapse

Abstract Relapsed acute lymphoblastic leukemia (ALL) is the leading cause of deaths of childhood cancer. Although relapse usually happens in the bone marrow, extramedullary relapse occasionally occurs including either the central nervous system or testis (<1–2%). We selected two pediatric ALL patients who experienced testicular relapse and interrogated their leukemic cells with exome sequencing. The sequencing results and clonality analyses suggest that relapse of patient D483 directly evolved from the leukemic clone at diagnosis which survived chemotherapy. In contrast, relapse leukemia cells (both bone marrow and testis) of patient D727 were likely derived from a common ancestral clone, and testicular relapse likely arose independently from the bone marrow relapsed leukemia. Our findings decipher the mutational spectra and shed light on the clonal evolution of two cases of pediatric ALL with testicular relapse. Presence of CREBBP/NT5C2 mutations suggests that a personalized therapeutic approach should be applied to these two patients

Transcriptional landscape of B cell precursor acute lymphoblastic leukemia based on an international study of 1,223 cases

Most B cell precursor acute lymphoblastic leukemia (BCP ALL) can be classified into known major genetic subtypes, while a substantial proportion of BCP ALL remains poorly characterized in relation to its underlying genomic abnormalities. We therefore initiated a large-scale international study to reanalyze and delineate the transcriptome landscape of 1,223 BCP ALL cases using RNA sequencing. Fourteen BCP ALL gene expression subgroups (G1 to G14) were identified. Apart from extending eight previously described subgroups (G1 to G8 associated with MEF2D fusions, TCF3–PBX1 fusions, ETV6–RUNX1–positive/ETV6–RUNX1–like, DUX4 fusions, ZNF384 fusions, BCR–ABL1/Ph–like, high hyperdiploidy, and KMT2A fusions), we defined six additional gene expression subgroups: G9 was associated with both PAX5 and CRLF2 fusions; G10 and G11 with mutations in PAX5 (p.P80R) and IKZF1 (p.N159Y), respectively; G12 with IGH–CEBPE fusion and mutations in ZEB2 (p.H1038R); and G13 and G14 with TCF3/4–HLF and NUTM1 fusions, respectively. In pediatric BCP ALL, subgroups G2 to G5 and G7 (51 to 65/67 chromosomes) were associated with low-risk, G7 (with ≤50 chromosomes) and G9 were intermediate-risk, whereas G1, G6, and G8 were defined as high-risk subgroups. In adult BCP ALL, G1, G2, G6, and G8 were associated with high risk, while G4, G5, and G7 had relatively favorable outcomes. This large-scale transcriptome sequence analysis of BCP ALL revealed distinct molecular subgroups that reflect discrete pathways of BCP ALL, informing disease classification and prognostic stratification. The combined results strongly advocate that RNA sequencing be introduced into the clinical diagnostic workup of BCP ALL. four decades, most of the recurring chromosomal abnormalities, including aneuploidy, chromosomal rearrangements/gene fusions (e.g., ETV6–RUNX1, BCR–ABL1, and TCF3–PBX1), and rearrangements of KMT2A (previously MLL), were identified by

Mutational Landscape of Pediatric Acute Lymphoblastic Leukemia

Current standard of care for patients with pediatric acute lymphoblastic leukemia (ALL) is mainly effective, with high remission rates after treatment. However, the genetic perturbations that give rise to this disease remain largely undefined, limiting the ability to address resistant tumors or develop less toxic targeted therapies. Here, we report the use of next-generation sequencing to interrogate the genetic and pathogenic mechanisms of 240 pediatric ALL cases with their matched remission samples. Commonly mutated genes fell into several categories, including RAS/receptor tyrosine kinases, epigenetic regulators, transcription factors involved in lineage commitment, and the p53/cell-cycle pathway. Unique recurrent mutational hotspots were observed in epigenetic regulators CREBBP (R1446C/H), WHSC1 (E1099K), and the tyrosine kinase FLT3 (K663R, N676K). The mutant WHSC1 was established as a gain-of-function oncogene, while the epigenetic regulator ARID1A and transcription factor CTCF were functionally identified as potential tumor suppressors. Analysis of 28 diagnosis/relapse trio patients plus 10 relapse cases revealed four evolutionary paths and uncovered the ordering of acquisition of mutations in these patients. This study provides a detailed mutational portrait of pediatric ALL and gives insights into the molecular pathogenesis of this disease. Cancer Res; 77(2); 390-400. ©2016 AACR

Mutational Landscape of Pediatric Acute Lymphoblastic Leukemia

Current standard of care for patients with pediatric acute lymphoblastic leukemia (ALL) is mainly effective, with high remission rates after treatment. However, the genetic perturbations that give rise to this disease remain largely undefined, limiting the ability to address resistant tumors or develop less toxic targeted therapies. Here we report the use of next generation sequencing to interrogate the genetic and pathogenic mechanisms of 240 pediatric ALL cases with their matched remission samples. Commonly mutated genes fell into several categories, including RAS/receptor tyrosine kinases, epigenetic regulators, transcription factors involved in lineage commitment and the p53/cell cycle pathway. Unique recurrent mutational hotspots were observed in epigenetic regulators CREBBP (R1446C/H), WHSC1 (E1099K) and the tyrosine kinase FLT3 (K663R, N676K). The mutant WHSC1 was established as a gain-of-function oncogene, while the epigenetic regulator ARID1A and transcription factor CTCF were functionally identified as potential tumor suppressors. Analysis of 28 diagnosis/relapse trio patients plus 10 relapse cases revealed four evolutionary paths and uncovered the ordering of acquisition of mutations in these patients. This study provides a detailed mutational portrait of pediatric ALL and gives insights into the molecular pathogenesis of this disease