Molecular Analysis of Hybrid Neurofibroma/Schwannoma Identifies Common Monosomy 22 and α-T-Catenin/CTNNA3 as a Novel Candidate Tumor Suppressor.

Neurofibromas and schwannomas are benign Schwann cell-derived peripheral nerve sheath tumors arising sporadically and within neurofibromatoses. Multiple tumors are a hallmark of neurofibromatosis type 1 (NF1) and type 2 (NF2) and schwannomatosis. Neurofibromas in NF1 and schwannomas in NF2 or schwannomatosis are defined by distinctive molecular hits. Among these, multiple hybrid neurofibromas/schwannomas may also appear, not yet being defined by a molecular background. We therefore performed molecular analysis of 22 hybrid neurofibromas/schwannomas using array comparative genomic hybridization, immunohistochemistry, quantitative RT-PCR, and functional analyses of cultured Schwann cells. Furthermore, we analyzed SMARCB1 by fluorescence in situ hybridization and multiplex ligation-dependent probe. Monosomy 22 was identified in 44% of tumors of tested patients with hybrid neurofibromas/schwannomas. In addition, in a single case, we detected focal deletion of the α-T-catenin/CTNNA3 gene (10q21.3). To further characterize this candidate, transient knockdown of α-T-catenin in Schwann cells was performed. CTNNA3 depleted cells showed cytoskeletal abnormalities and reduced E-cadherin expression, indicating epithelial-mesenchymal transition-like abnormalities. To conclude, we uncovered loss of chromosome 22 in almost half of all cases with hybrid neurofibromas/schwannomas of patients with multiple peripheral nerve sheath tumors. We tagged α-T-catenin/CTNNA3 as a novel candidate gene. Our functional investigations might indicate involvement of α-T-catenin/CTNNA3 in the biology of peripheral nerve sheath tumors.

A cyclin-D1 interaction with BAX underlies its oncogenic role and potential as a therapeutic target in mantle cell lymphoma.

The chromosomal translocation t(11;14)(q13;q32) leading to cyclin-D1 overexpression plays an essential role in the development of mantle cell lymphoma (MCL), an aggressive tumor that remains incurable with current treatment strategies. Cyclin-D1 has been postulated as an effective therapeutic target, but the evaluation of this target has been hampered by our incomplete understanding of its oncogenic functions and by the lack of valid MCL murine models. To address these issues, we generated a cyclin-D1-driven mouse model in which cyclin-D1 expression can be regulated externally. These mice developed cyclin-D1-expressing lymphomas capable of recapitulating features of human MCL. We found that cyclin-D1 inactivation was not sufficient to induce lymphoma regression in vivo; however, using a combination of in vitro and in vivo assays, we identified a novel prosurvival cyclin-D1 function in MCL cells. Specifically, we found that cyclin-D1, besides increasing cell proliferation through deregulation of the cell cycle at the G(1)-S transition, sequestrates the proapoptotic protein BAX in the cytoplasm, thereby favoring BCL2's antiapoptotic function. Accordingly, cyclin-D1 inhibition sensitized the lymphoma cells to apoptosis through BAX release. Thus, genetic or pharmacologic targeting of cyclin-D1 combined with a proapoptotic BH3 mimetic synergistically killed the cyclin-D1-expressing murine lymphomas, human MCL cell lines, and primary lymphoma cells. Our study identifies a role of cyclin-D1 in deregulating apoptosis in MCL cells, and highlights the potential benefit of simultaneously targeting cyclin-D1 and survival pathways in patients with MCL. This effective combination therapy also might be exploited in other cyclin-D1-expressing tumors.

Germline nonsense mutation and somatic inactivation of SMARCA4/BRG1 in a family with rhabdoid tumor predisposition syndrome.

Rhabdoid tumors of early infancy are highly aggressive with consequent poor prognosis. Most cases show inactivation of the SMARCB1 (also known as INI1 and hSNF5) tumor suppressor, a core member of the ATP-dependent SWI/SNF chromatin-remodeling complex. Familial cases, described as rhabdoid tumor predisposition syndrome (RTPS), have been linked to heterozygous SMARCB1 germline mutations. We identified inactivation of another member of the SWI/SNF chromatin-remodeling complex, its ATPase subunit SMARCA4 (also known as BRG1), due to a SMARCA4/BRG1 germline mutation and loss of heterozygosity by uniparental disomy in the tumor cells of two sisters with rhabdoid tumors lacking SMARCB1 mutations. SMARCA4 is thus a second member of the SWI/SNF complex involved in cancer predisposition. Its general involvement in other tumor entities remains to be established.

Response of ETV6-FLT3-positive myeloid/lymphoid neoplasm with eosinophilia to inhibitors of FMS-like tyrosine kinase 3.

Imatinib-resistant tyrosine kinase (TK) fusions involving FGFR1, JAK2, or FLT3 are rare but recurrent in patients with eosinophilia-associated neoplasms. We report here 2 male patients with ETV6-FLT3(+) myeloid/lymphoid neoplasms with eosinophilia who were treated with the multitargeted TK inhibitors sunitinib and sorafenib. Patient 1 achieved rapid complete hematologic response and complete cytogenetic response after 3 months of taking sunitinib. A secondary blast phase caused by clonal evolution was diagnosed after 6 months. He achieved a second complete hematologic response after taking sorafenib but relapsed 2 months later. An N841K point mutation within the TK domain of FLT3, previously reported in acute myeloid leukemia and potentially conferring resistance to sorafenib, was subsequently identified. Patient 2 was heavily pretreated according to the initial diagnosis of T-lymphoblastic lymphoma and died in sunitinib-induced pancytopenia. This report highlights the importance of a careful diagnostic workup for eosinophilia-associated neoplasms to evaluate the possibility of TK inhibitor therapy.

Translocations activating IRF4 identify a subtype of germinal center-derived B-cell lymphoma affecting predominantly children and young adults.

The prognosis of germinal center-derived B-cell (GCB) lymphomas, including follicular lymphoma and diffuse large-B-cell lymphoma (DLBCL), strongly depends on age. Children have a more favorable outcome than adults. It is not known whether this is because of differences in host characteristics, treatment protocols, or tumor biology, including the presence of chromosomal alterations. By screening for novel IGH translocation partners in pediatric and adult lymphomas, we identified chromosomal translocations juxtaposing the IRF4 oncogene next to one of the immunoglobulin (IG) loci as a novel recurrent aberration in mature B-cell lymphoma. FISH revealed 20 of 427 lymphomas to carry an IG/IRF4-fusion. Those were predominantly GCB-type DLBCL or follicular lymphoma grade 3, shared strong expression of IRF4/MUM1 and BCL6, and lacked PRDM1/BLIMP1 expression and t(14;18)/BCL2 breaks. BCL6 aberrations were common. The gene expression profile of IG/IRF4-positive lymphomas differed from other subtypes of DLBCL. A classifier for IG/IRF4 positivity containing 27 genes allowed accurate prediction. IG/IRF4 positivity was associated with young age and a favorable outcome. Our results suggest IRF4 translocations to be primary alterations in a molecularly defined subset of GCB-derived lymphomas. The probability for this subtype of lymphoma significantly decreases with age, suggesting that diversity in tumor biology might contribute to the age-dependent differences in prognosis of lymphoma.

The CBFA2T3/ACSF3 locus is recurrently involved in IGH chromosomal translocation t(14;16)(q32;q24) in pediatric B-cell lymphoma with germinal center phenotype.

Translocations involving immunoglobulin (IG) loci are the hallmarks of several subtypes of B-cell lymphoma. Common to these translocations is that cellular proto-oncogenes come under the influence of IG regulatory elements leading to deregulated expression. In case of a breakpoint in the IGH switch region, oncogene activation can take place on both derivative chromosomes, which means that in principle one translocation can result in concurrent activation of two genes. By fluorescence in situ hybridization (FISH), we identified a case of leukemic B-cell lymphoma in a child with an IGH break and unknown partner. Subsequent long-distance inverse PCR revealed fusion of IGH Sl in 14q32 and the 50 region of CBFA2T3 in 16q24.3, suggesting presence of the t(14;16)(q32;q24.3). Candidate oncogenes targeted through this translocation are CBFA2T3 and ACSF3, which could be activated on der(16) and der(14), respectively. FISH screening of a population-based cohort of B-cell lymphomas from a prospective trial for the treatment of lymphoma in childhood (BFM-NHL) identified additionally a follicular lymphoma Grade 3/diffuse large B-cell lymphoma with IGH-CBFA2T3/ACSF3 juxtaposition. Both lymphomas shared expression of CD10 and CD20 in the absence of TdT, suggesting a germinal center (GC) B-cell origin. Our data indicate that the CBFA2T3/ACSF3 locus is a novel recurrent oncogenic target of IGH translocations, which might contribute to the pathogenesis of pediatric GC-derived B-cell lymphoma.

Genetic lesions of the TRAF3 and MAP3K14 genes in classical Hodgkin lymphoma.

Hodgkin and Reed/Sternberg (HRS) cells in classical Hodgkin lymphoma (cHL) show constitutive activation of nuclear factor (NF)-κB. Several genetic lesions contribute to this deregulated NF-κB activity. Here, we analysed two further NF-κB regulators for genetic lesions, the inhibitory factor TRAF3 and the key signalling component of the alternative NF-κB pathway, MAP3K14 (NIK). Single nucleotide polymorphism (SNP) array analysis of cHL cell lines revealed a uniparental disomy of the long arm of chromosome 14 associated with a biallelic deletion of TRAF3 located on this chromosome in cell line U-HO1. Cloning of the deletion breakpoint showed a 123 371 bp deletion. No inactivating mutations of TRAF3 were found in six other cHL cell lines or in microdissected HRS cells from seven cHL. However, in primary cHL samples interphase cytogenetic analyses revealed signal patterns indicating monoallelic deletion of TRAF3 in 3/20 other cases. SNP array analysis revealed a gain of copy number for MAP3K14 in three cHL cell lines. Gains of MAP3K14 were detected in 5/16 cases of primary cHL. In conclusion, in rare instances, HRS cells harbour inactivating mutations of the TRAF3 gene and recurrently show gains of MAP3K14, indicating that more components of NF-κB signalling show genetic lesions in HRS cells than previously known.

Defining the prognosis of early stage chronic lymphocytic leukaemia patients.

Approximately 70% of chronic lymphocytic leukaemia (CLL) patients present with early stage disease, therefore defining which patients will progress and require treatment is a major clinical challenge. Here, we present the largest study of prognostic markers ever carried out in Binet stage A patients (n = 1154) with a median follow-up of 8 years. We assessed the prognostic impact of lymphocyte doubling time (LDT), immunoglobulin gene (IGHV) mutation status, CD38 expression, ZAP-70 expression and fluorescence in situ hybridization (FISH) cytogenetics with regards to time to first treatment (TTFT) and overall survival (OS). Univariate analysis revealed LDT as the most prognostic parameter for TTFT, with IGHV mutation status most prognostic for OS. CD38 expression, ZAP-70 expression and FISH were also prognostic variables; combinations of these markers increased prognostic power in concordant cases. Multivariate analysis revealed that only LDT, IGHV mutation status, CD38 and age at diagnosis were independent prognostic variables for TTFT and OS. Therefore, IGHV mutation status and CD38 expression have independent prognostic value in early stage CLL and should be performed as part of the routine diagnostic workup. ZAP-70 expression and FISH were not independent prognostic markers in early stage disease and can be omitted at diagnosis but FISH analysis should be undertaken at disease progression to direct treatment strategy.

Presence of the P2RY8-CRLF2 rearrangement is associated with a poor prognosis in non-high-risk precursor B-cell acute lymphoblastic leukemia in children treated according to the ALL-BFM 2000 protocol.

High-level expression of the cytokine receptor-like factor 2 gene, CRLF2, in precursor B-cell acute lymphoblastic leukemia (pB-ALL) was shown to be caused by a translocation involving the IGH@ locus or a deletion juxtaposing CRLF2 with the P2RY8 promoter. To assess its possible prognostic value, CRLF2 expression was analyzed in 555 childhood pB-ALL patients treated according to the Acute Lymphoblastic Leukemia Berlin-Frankfurt-Münster 2000 (ALL-BFM 2000) protocol. Besides CRLF2 rearrangements, high-level CRLF2 expression was seen in cases with supernumerary copies of the CRLF2 locus. On the basis of the detection of CRLF2 rearrangements, a CRLF2 high-expression group (n = 49) was defined. This group had a 6-year relapse incidence of 31% plus or minus 8% compared with 11% plus or minus 1% in the CRLF2 low-expression group (P = .006). This difference was mainly attributable to an extremely high incidence of relapse (71% +/- 19%) in non-high-risk patients with P2RY8-CRLF2 rearrangement. The assessment of CRLF2 aberrations may therefore serve as new stratification tool in Berlin-Frankfurt-Münster-based protocols by identifying additional high-risk patients who may benefit from an intensified and/or targeted treatment.

Deregulation of the telomerase reverse transcriptase (TERT) gene by chromosomal translocations in B-cell malignancies.

Sequence variants at the TERT-CLPTM1L locus in chromosome 5p have been recently associated with disposition for various cancers. Here we show that this locus including the gene encoding the telomerase reverse-transcriptase TERT at 5p13.33 is rarely but recurrently targeted by somatic chromosomal translocations to IGH and non-IG loci in B-cell neoplasms, including acute lymphoblastic leukemia, chronic lymphocytic leukemia, mantle cell lymphoma and splenic marginal zone lymphoma. In addition, cases with genomic amplification of TERT locus were identified. Tumors bearing chromosomal aberrations involving TERT showed higher TERT transcriptional expression and increased telomerase activity. These data suggest that deregulation of TERT gene by chromosomal abnormalities leading to increased telomerase activity might contribute to B-cell lymphomagenesis.

Cytogenetic aberrations and their prognostic value in a series of 330 splenic marginal zone B-cell lymphomas: a multicenter study of the Splenic B-Cell Lymphoma Group.

We conducted a retrospective collaborative study to cytogenetically characterize splenic marginal zone lymphoma (SMZL) and ascertain the prognostic value of chromosomal aberrations. Of 330 cases, 72% displayed an aberrant karyotype, 53% were complex, and 29% had a single aberration. The predominant aberrations were gains of 3/3q and 12q, deletions of 7q and 6q and translocations involving 8q/1q/14q. CD5 expression was detected in 39 of 158 cases (25%). The cytogenetic makeup of the CD5(+) group differed significantly from that of the CD5(-) group. Cases with unmutated IGHV were significantly associated with deletions of 7q and TP53. A strong association was noted between usage of the IGVH1-2 and deletion 7q, 14q alterations, and abnormal karyotype. On univariate analysis, patients with more than or equal to 2 aberrations, 14q alterations, and TP53 deletions had the shortest survival; 7q deletion did not affect survival. On multivariate analysis, cytogenetic aberrations did not retain prognostic significance; the parameters negatively affecting survival were hemoglobin and age. In conclusion, the cytogenetic profile of SMZL is distinct from other B-cell lymphomas. Complexity of the karyotype, 14q aberrations, and TP53 deletions are poor prognostic indicators and may be considered together with other clinicobiologic parameters to ascertain the prognosis of SMZL.

Fast approach for clarification of chromosomal aberrations by using LM-PCR and FT-CGH in leukaemic sample.

Chromosomal abnormalities, like deletions, amplifications, inversions or translocations, are recurrent features in haematological malignancies. However, the precise molecular breakpoints are frequently not determined. Here we describe a rapid analysis of genetic imbalances combining fine tiling comparative genomic hybridization (FT-CGH) and ligation-mediated PCR (LM-PCR). We clarified an inv(14)(q11q32) in a case of T cell acute lymphoblastic leukaemia with a breakpoint in the TRA/D in 68% of cells detected by fluorescence in situ hybridization. FT-CGH showed several mono- and biallelic losses within TRA/D. LM-PCR disclosed a TRA/D rearrangement on one allele. The other allele revealed an inv(14)(q11q32), joining TRDD2 at 21,977,000 of 14q11 together with the IGH locus at 105,948,000 and 3'-sequence of TRAC at 22,092,000 joined together with IGHV4-61 at 106,166,000. This sensitive approach can unravel complex chromosomal abnormalities in patient samples with a limited amount of aberrant cells and may lead to better diagnostic and therapeutic options.

Outcome of Ordinary Polymorphous Adenocarcinomas of the Salivary Glands in Comparison With Papillary and Cribriform Subtypes.

BACKGROUND/AIM: Polymorphous adenocarcinoma (PAC) is a low-grade salivary gland malignancy in contrast to variants with papillary (PAP) or cribriform (CASG) architecture and confers the second most common malignancy of minor salivary glands. Our study aimed to identify prognostic factors and to evaluate histomorphological and molecular diagnostic criteria of PACs. PATIENTS AND METHODS: A series of 155 PACs, including 10 PAPs and 12 CASGs from the population-based Cancer Registry of North Rhine-Westphalia (LKR-NRW) and the Hamburg Salivary Gland Reference Centre (HRC) were analyzed. RESULTS: One fifth of the tumors were located in the major salivary glands and PACS/CASGS invariably lacked p40 expression. Fifty-two percent of PACs showed a PRKD1 E710D mutation. Ordinary PACs had a disease-specific 10-year survival probability of 97% compared to 90% when combining PAPs and CASGs. T-stage at diagnosis was a prognostic factor with 98% for stages T1/T2 versus 75% for T3/T4. CONCLUSION: Diagnostic algorithms for the PAC/CASG spectrum of tumors need to be improved and should include molecular markers.

Clinical and molecular features in patients with atypical teratoid rhabdoid tumor or malignant rhabdoid tumor.

The SMARCB1 gene status in 50 patients with atypical teratoid rhabdoid tumor and/or malignant rhabdoid tumor recruited to a German registry was prospectively analyzed with FISH and PCR. Altogether we found 40 SMARCB1 mutations in 28 patients. Two patients were positive for SMARCB1 staining at immunochemistry. Germline mutations were identified in 10 of 41 patients with CNS disease, including three large heterozygous deletions, six truncating mutations and one donor splice site mutation. No missense mutation was identified. Analysis of first degree relatives did not detect any carriers. Mutations were distributed over the SMARCB1-gene without particular clustering. No germline mutation was found in nine patients without CNS disease. Patients with germline mutation had a lower median age at diagnosis in comparison to those without detectable germline mutation (5.5 vs. 13 months, P = 0.001), a higher rate of primary multicentric CNS disease (5/10 vs. 5/36) and synchronous or metachronous mixed CNS and extracranial disease (4/10 vs. 1/36). Two year overall survival was 0% in patients with germline mutation and 48% in those without detectable germline mutation (P < 0.001). Patients with germline mutation of SMARCB1 manifest at an early age and have a very high risk for progression which has to be considered with respect to the outcome of further treatment studies.

Rare occurrence of biallelic CYLD gene mutations in classical Hodgkin lymphoma.

Survival of the malignant Hodgkin and Reed/Sternberg (HRS) cells in classical Hodgkin lymphoma (cHL) is dependent on constitutive activation of the nuclear factor kappaB (NF-kappaB) transcription factor. The deubiquitinating enzyme CYLD is a negative regulator of NF-kappaB and known to function as a tumor suppressor. To determine whether CYLD mutations play a role in cHL pathogenesis, we sequenced the gene in cHL cell lines and microdissected HRS cells obtained from lymph-node biopsies. A biallelic inactivation by mutations was found in the cHL cell-line KM-H2. However, the other seven cHL cell lines analyzed and HRS cells of 10 primary cHL cases did not show any mutations. By interphase cytogenetics, a (sub)clonal biallelic CYLD deletion was observed by interphase cytogenetics in 1 of 29 primary cHL, whereas signal patterns indicating decreased CYLD copy numbers were observed in a total of 10 of 29 primary cases. Our results suggest that biallelic CYLD mutations are rarely involved in cHL pathogenesis. Nevertheless, it is remarkable that KM-H2 cells, besides the CYLD mutations, also carry inactivating mutations in the genes of two other NF-kappaB inhibitors, that is, NFKBIA and TNFAIP3, exemplifying that multiple lesions in regulators of this signaling pathway can likely cooperatively contribute to the strong NF-kappaB activity of these cells.

Genomic insights into the pathogenesis of Epstein-Barr virus-associated diffuse large B-cell lymphoma by whole-genome and targeted amplicon sequencing.

Epstein-Barr virus (EBV)-associated diffuse large B-cell lymphoma not otherwise specified (DLBCL NOS) constitute a distinct clinicopathological entity in the current World Health Organization (WHO) classification. However, its genomic features remain sparsely characterized. Here, we combine whole-genome sequencing (WGS), targeted amplicon sequencing (tNGS), and fluorescence in situ hybridization (FISH) from 47 EBV + DLBCL (NOS) cases to delineate the genomic landscape of this rare disease. Integrated WGS and tNGS analysis clearly distinguished this tumor type from EBV-negative DLBCL due to frequent mutations in ARID1A (45%), KMT2A/KMT2D (32/30%), ANKRD11 (32%), or NOTCH2 (32%). WGS uncovered structural aberrations including 6q deletions (5/8 patients), which were subsequently validated by FISH (14/32 cases). Expanding on previous reports, we identified recurrent alterations in CCR6 (15%), DAPK1 (15%), TNFRSF21 (13%), CCR7 (11%), and YY1 (6%). Lastly, functional annotation of the mutational landscape by sequential gene set enrichment and network propagation predicted an effect on the nuclear factor κB (NFκB) pathway (CSNK2A2, CARD10), IL6/JAK/STAT (SOCS1/3, STAT3), and WNT signaling (FRAT1, SFRP5) alongside aberrations in immunological processes, such as interferon response. This first comprehensive description of EBV + DLBCL (NOS) tumors substantiates the evidence of its pathobiological independence and helps stratify the molecular taxonomy of aggressive lymphomas in the effort for future therapeutic strategies.

High resolution SNP array genomic profiling of peripheral T cell lymphomas, not otherwise specified, identifies a subgroup with chromosomal aberrations affecting the REL locus.

Little is known about genomic aberrations in peripheral T cell lymphoma, not otherwise specified (PTCL NOS). We studied 47 PTCL NOS by 250k GeneChip single nucleotide polymorphism arrays and detected genomic imbalances in 22 of the cases. Recurrent gains and losses were identified, including gains of chromosome regions 1q32-43, 2p15-16, 7, 8q24, 11q14-25, 17q11-21 and 21q11-21 (> or = 5 cases each) as well as losses of chromosome regions 1p35-36, 5q33, 6p22, 6q16, 6q21-22, 8p21-23, 9p21, 10p11-12, 10q11-22, 10q25-26, 13q14, 15q24, 16q22, 16q24, 17p11, 17p13 and Xp22 (> or = 4 cases each). Genomic imbalances affected several regions containing members of nuclear factor-kappaB signalling and genes involved in cell cycle control. Gains of 2p15-16 were confirmed in each of three cases analysed by fluorescence in situ hybridization (FISH) and were associated with breakpoints at the REL locus in two of these cases. Three additional cases with gains of the REL locus were detected by FISH among 18 further PTCL NOS. Five of 27 PTCL NOS investigated showed nuclear expression of the REL protein by immunohistochemistry, partly associated with genomic gains of the REL locus. Therefore, in a subgroup of PTCL NOS gains/rearrangements of REL and expression of REL protein may be of pathogenetic relevance.

Mutations of CARD11 but not TNFAIP3 may activate the NF-kappaB pathway in primary CNS lymphoma.

Primary CNS lymphoma (PCNSL), the intracerebral subgroup of diffuse large B cell lymphoma (DLBCL), shows evidence for aberrant activation of the nuclear factor (NF)-kappaB pathway. In order to identify potential activators of the NF-kappaB complex, we analyzed the CARD11 and TNFAIP3 genes for the presence of somatic mutations and TNFAIP3 for aberrant promoter methylation in PCNSL. We also compared PCNSL to spinal DLBCL, because CARD11 and TNFAIP3 mutations have been described in systemic DLBCL. CARD11 mutations, located in the coiled-coil region, which may activate NF-kappaB, were detected in 16% (5/32) of PCNSL, while TNFAIP3 mutations were detected in 3% (1/32) of PCNSL. In PCNSL, all CARD11 mutations were heterozygous, in-frame, induced amino acid exchanges, and presumably led to activation of this oncogene. Spinal DLBCL harbored mutations of CARD11 and TNFAIP3 in 10% (1/10) and 20% (2/10) of cases, respectively. In both PCNSL and spinal DLBCL, mutations in CARD11 and TNFAIP3 were mutually exclusive. TNFAIP3 was unmethylated in all PCNSLs (30/30) and spinal DLBCLs (10/10). We conclude that mutations of the oncogene CARD11 may contribute to NF-kappaB activation and thereby play a role in the pathogenesis of PCNSL, while, in contrast to systemic DLBCL, inactivation of TNFAIP3 either by mutation or methylation seems to be of minor significance.

Pediatric follicular lymphoma--a clinico-pathological study of a population-based series of patients treated within the Non-Hodgkin's Lymphoma--Berlin-Frankfurt-Munster (NHL-BFM) multicenter trials.

UNLABELLED: Background Pediatric follicular lymphoma has recently been recognized as a novel variant of follicular lymphoma in the World Health Organization classification of lymphomas. Given the rarity of the disease, histopathological and genetic data on this type of lymphoma are still scarce. DESIGN AND METHODS: We analyzed 25 cases of pediatric follicular lymphoma (patients aged

Molecular characterization of a novel chromosomal translocation t(12;14)(q23;q11.2) in T-lymphoblastic lymphoma between the T-cell receptor delta-deleting elements (TRDREC and TRAJ61) and the hypothetical gene C12orf42.

Chromosomal aberrations have diagnostic, prognostic, and therapeutic relevance in hematologic malignancies. By combining fine-tiling comparative genomic hybridization (FT-CGH) and ligation-mediated PCR (LM-PCR), we established a fast, robust approach to precisely characterize chromosomal breakpoints. Using this approach, we clarified at the molecular level novel chromosomal translocation t(12;14)(q23;q11.2) in T-lymphoblastic lymphoma. The translocation occurred during the deletional rearrangement of the T-cell receptor delta gene (TRD), which is a pivotal step in T cell differentiation toward the alpha/beta vs. the gamma/delta lineage. We found that this rearrangement disrupted the hypothetical gene C12orf42 and brought the Achaete-scute complex homolog 1 gene into proximity of the TRA enhancer, which encodes a member of the basic helix-loop-helix family of transcription factors and is overexpressed in thyroid and lung cancers.