The family/class of the large B-cell lymphomas (LBCL) in the 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumors (WHO-HAEM5) features only a few major changes as compared to the 4th edition. In most entities, there are only subtle changes, many of them only representing some minor modifications in diagnostic terms. Major changes have been made in the diffuse large B-cell lymphomas (DLBCL)/high-grade B-cell lymphomas (HGBL) associated with MYC and BCL2 and/or BCL6 rearrangements. This category now consists of MYC and BCL2 rearranged cases exclusively, while the MYC/BCL6 double hit lymphomas now constitute genetic subtypes of DLBCL, not otherwise specified (NOS) or of HGBL, NOS. Other major changes are the conceptual merger of lymphomas arising in immune-privileged sites and the description of LBCL arising in the setting of immune dysregulation/deficiency. In addition, novel findings concerning underlying biological mechanisms in the pathogenesis of the different entities are provided.

The conceptual description of Follicular lymphoma (FL) in the 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumors (WHO-HAEM5) has undergone significant revision. The vast majority of FL (85%) with a follicular growth pattern are composed of centrocytes and centroblasts, harbor the t(14;18)(q32;q21) translocation and are now termed classic FL (cFL). They are set apart from three related subtypes, FL with predominantly follicular growth pattern, FL with unusual cytological features (uFL) and follicular large B-cell lymphoma (FLBCL). In contrast to the revised 4th edition of the WHO classification of haematolymphoid tumors (WHO-HAEM4R), grading of cFL is no longer mandatory. FL with a predominantly diffuse growth pattern had been previously recognized in WHO-HAEM4R. It frequently occurs as a large tumor in the inguinal region and is associated with CD23 expression. An absence of the IGH::BCL2 fusion and frequent STAT6 mutations along with 1p36 deletion or TNFRSF14 mutation is typical. The newly introduced subtype of uFL includes two subsets that significantly diverge from cFL: one with "blastoid" and one with "large centrocyte" variant cytological features. uFL more frequently displays variant immunophenotypic and genotypic features. FLBCL is largely identical to WHO-HAEM4R FL grade 3B and renaming was done for reasons of consistency throughout the classification. In-situ follicular B-cell neoplasm, pediatric-type FL, duodenal-type FL and primary cutaneous follicle center lymphoma are categorized as discrete entities. In addition, novel findings concerning underlying biological mechanisms in the pathogenesis of early and systemic follicular lymphoma will be presented.

Burkitt lymphoma (BL) is a B cell lymphoma composed of monomorphic medium-sized blastic cells with basophilic cytoplasm and a high proliferation index. BL has a characteristic immunophenotype of CD10 and BCL6 positive and BCL2 negative and harbours MYC gene rearrangements (MYCR) in >90% of the cases. Owing to its highly aggressive nature, intensified chemotherapy regimens are usually administered, requiring an exact diagnosis. Since the diagnosis usually warrants an integration of morphologic, immunophenotypic and genetic findings and because there is a morphologic overlap with the new WHO category of high-grade B cell lymphoma, not otherwise specified (HGBL, NOS) and some cases of diffuse large B cell lymphoma (DLBCL), we wanted to test the distinctiveness of the CD10+, BCL6+, BCL2- and MYCR positive immunopheno-genotype in a large cohort of >1000 DLBCL and HGBL. Only 9/982 DLBCL classified by an expert panel of haematopathologists (0.9%) displayed a single MYCR and were CD10+, BCL6+ and BCL2-. In a similar fashion, only one out of 32 HGBL, NOS (3%) displayed the “Burkitt-like” genetic/immunophenotypic constitution. The samples of non-BL showing the BL-typic immunopheno-genotype, interestingly, harboured higher copy number variations (CNV) by OncoScan analysis (mean 7.3 CNVs/sample; range: 2–13 vs. 2.4; range 0–6) and were also distinct from pleomorphic BL cases regarding their mutational spectrum by NGS analysis. This implies that the characteristic immunophenotype of BL, in concert with a single MYCR, is uncommon in these aggressive lymphomas, and that this constellation favours BL.

The vast majority of classical Hodgkin lymphoma (CHL) are derived from germinal center B-cells, and owing to its characteristic nuclear expression of the B-cell transcription factor PAX5, CHL can b...

The immunoblastic variant of diffuse large B-cell lymphoma (IB-DLBCL) has recently been recognized as an aggressive lymphoma type with inferior prognosis as compared with other DLBCL variants. At the same time, the presence of MYC rearrangements in DLBCL has been shown to indicate shorter survival in R-CHOP-treated patients. In this study, we investigated the occurrence of MYC gene rearrangements in IB-DLBCL versus non-IB-DLBCL in a large series. Using fluorescence in situ hybridization with an MYC break-apart and MYC-IGH fusion probe, we found that 13/39 evaluable IB-DLBCLs (33%) harbor translocations involving MYC, in contrast with only 5/68 (7%) in the non-IB-DLBCL group (P<0.01). The immunoglobulin heavy chain gene (IGH) was the translocation partner in all rearrangements (100%) involving MYC in IB-DLBCL, which is in contrast to what has been reported for DLBCL in the literature (50% to 70%). Moreover, MYC rearrangements occurred as the sole translocation in the majority of cases (77%), whereas across all DLBCLs the majority of MYC-rearranged cases carry additional rearrangements of either BCL2 and/or BCL6 genes (between 58% and 83% of cases). Finally, MYC-rearranged IB-DLBCLs were CD10 positive in 62% (8/13), whereas this was an uncommon feature in MYC germline IB-DLBCLs (15%). In conclusion, IB-DLBCLs are genetically characterized by frequent MYC-IGH translocations that often occur without additional BCL2 and/or BCL6 translocations. The activation of MYC, therefore, may be an important pathogenetic feature in IB-DLBCL.

Cools, J., Bilhou-Nabera, C., Wlodarska, I., Cabrol, C., Talmant, P., Bernard, P., Hagemeijer, A. & Marynen, P. (1999) Fusion of a novel gene, BTL, to ETV6 in acute myeloid leukemias with a t(4;12)(q11-q12;p13). Blood, 94, 1820–1824. Cools, J., Mentens, N., Odero, M.D., Peeters, P., Wlodarska, I., Delforge, M., Hagemeijer, A. & Marynen, P. (2002) Evidence for position effects as a variant ETV6-mediated leukemogenic mechanism in myeloid leukemias with a t(4;12) (q11-q12;p13) or t(5;12)(q31;p13). Blood, 99, 1776–1784. De Weer, A., Speleman, F., Cauwelier, B., Van Roy, N., Yigit, N., Verhasselt, B., De Moerloose, B., Benoit, Y., Noens, L., Selleslag, D., Lippert, E., Struski, S., Bastard, C., De Paepe, A., Vandenberhge, P., Hagemeijer, A., Dastugue, N. & Poppe, B. (2008) EVI1 overexpression in t(3;17) positive myeloid malignancies results from juxstaposition of EVI1 to the MSI2 locus at 17q22. Haematologica, 93, 1903– 1907. Di Giacomo, D., Pierini, V., Barba, G., Ceccarelli, V., Vecchini, A. & Mecucci, C. (2014) Blast crisis Ph+ chronic myeloid leukemia with NUP98/ HOXA13 up-regulating MSI2. Molecular Cytogenetics, 7, 42. doi:10.1186/1755-8166-7-42. eCollection Harada, H., Asou, H., Kyo, T., Asaoku, H., Iwato, K., Dohy, H., Oda, K., Harada, Y., Kita, K. & Kamada, N. (1995) A specific chromosome abnormality of t(4;12)(q11–12;p13) in CD7 acute leukemia. British Journal of Haematology, 90, 850– 854. Lee, T.I., Jenner, R.G., Boyer, L.A., Guenther, M.G., Levine, S.S., Kumar, R.M., Chevalier, B., Johnstone, S.E., Cole, M.F., Isono, K-i, Koseki, H., Fuchikami, T., Abe, K., Murray, H.L., Zucker, J.P., Yuan, B., Bell, G.W., Herbolsheimer, E., Hannett, N.M., Sun, K., Odom, D.T., Otte, A.P., Volkert, T.L., Bartel, D.P., Melton, D.A., Gifford, D.K., Jaenisch, R. & Young, R.A. (2006) Control of development regulators by polycomb in human embryonic stem cells. Cell, 125, 301–313. Lopez-Juarez, A., Howard, J., Ullom, K., Howard, L., Grande, A., Pardo, A., Waclaw, R., Sun, Y.Y., Yang, D., Kuan, C.Y., Campbell, K. & Nakafuku, M. (2013) Gsx2 controls regionspecific activation of neural stem cells and injury-induced neurogenesis in the adult subventricular zone. Genes & Development, 27, 1272–1287. Marcucci, G., Haferlach, T. & D€ ohner, H. (2011) Molecular genetics of adult acute myeloid leukemia: prognostic and therapeutic implications. Journal Of Clinical Oncology, 29, 475–486. Soler, G., Kaltenbach, S., Dobbelstein, S., Broccardo, C., Radford, I., Mozziconacci, M.J., Bernard, O.A., Penard-Lacronique, V., Delabesse, E. & Romana, S.P. (2013) Identification of GSX2 and AF10 as NUP98 partner genes in myeloid malignancies. Blood Cancer Journal, 3, e124. Squazzo, S.L., O’Geen, H., Komashko, V.M., Krig, S.R., Jin, V.X., Jang, S.W., Margueron, R., Reinberg, D., Green, R. & Farnham, P.J. (2006) Suz12 binds to silenced regions of the genome in a cell-type-specific manner. Genome Research, 16, 890–900.

Models of brain stem ventral respiratory column (VRC) circuits typically emphasize populations of neurons, each active during a particular phase of the respiratory cycle. We have proposed that “tonic” pericolumnar expiratory (t-E) neurons tune breathing during baroreceptor-evoked reductions and central chemoreceptor-evoked enhancements of inspiratory (I) drive. The aims of this study were to further characterize the coordinated activity of t-E neurons and test the hypothesis that peripheral chemoreceptors also modulate drive via inhibition of t-E neurons and disinhibition of their inspiratory neuron targets. Spike trains of 828 VRC neurons were acquired by multielectrode arrays along with phrenic nerve signals from 22 decerebrate, vagotomized, neuromuscularly blocked, artificially ventilated adult cats. Forty-eight of 191 t-E neurons fired synchronously with another t-E neuron as indicated by cross-correlogram central peaks; 32 of the 39 synchronous pairs were elements of groups with mutual pairwise correlations. Gravitational clustering identified fluctuations in t-E neuron synchrony. A network model supported the prediction that inhibitory populations with spike synchrony reduce target neuron firing probabilities, resulting in offset or central correlogram troughs. In five animals, stimulation of carotid chemoreceptors evoked changes in the firing rates of 179 of 240 neurons. Thirty-two neuron pairs had correlogram troughs consistent with convergent and divergent t-E inhibition of I cells and disinhibitory enhancement of drive. Four of 10 t-E neurons that responded to sequential stimulation of peripheral and central chemoreceptors triggered 25 cross-correlograms with offset features. The results support the hypothesis that multiple afferent systems dynamically tune inspiratory drive in part via coordinated t-E neurons.

Few data are available regarding the reliability of fluorescence in-situ hybridization (FISH), especially for chromosomal deletions, in high-throughput settings using tissue microarrays (TMAs). We performed a comprehensive FISH study for the detection of chromosomal translocations and deletions in formalin-fixed and paraffin-embedded (FFPE) tumor specimens arranged in TMA format. We analyzed 46 B-cell lymphoma (B-NHL) specimens with known karyotypes for translocations of IGH-, BCL2-, BCL6- and MYC-genes. Locus-specific DNA probes were used for the detection of deletions in chromosome bands 6q21 and 9p21 in 62 follicular lymphomas (FL) and six malignant mesothelioma (MM) samples, respectively. To test for aberrant signals generated by truncation of nuclei following sectioning of FFPE tissue samples, cell line dilutions with 9p21-deletions were embedded into paraffin blocks. The overall TMA hybridization efficiency was 94%. FISH results regarding translocations matched karyotyping data in 93%. As for chromosomal deletions, sectioning artefacts occurred in 17% to 25% of cells, suggesting that the proportion of cells showing deletions should exceed 25% to be reliably detectable. In conclusion, FISH represents a robust tool for the detection of structural as well as numerical aberrations in FFPE tissue samples in a TMA-based high-throughput setting, when rigorous cut-off values and appropriate controls are maintained, and, of note, was superior to quantitative PCR approaches.

No prospective studies are available to date evaluating the combined analysis of chromosomal alterations via interphase FISH in different soft tissue sarcoma (STS) subtypes. We tested 64 consecutive sarcoma specimens with FISH probes to detect aberrations specific for a given STS subtype. We first determined the translocation frequency in the specific STS subtypes in 48 tumors, with the primary pathological diagnosis as the gold standard. Subsequently, to evaluate sensitivity and specificity, all FISH probes were hybridized to 16 STS of hitherto unknown diagnosis. DDIT3 translocations occurred in 8/10 (80%) of myxoid liposarcomas. FOXO1 translocations were noted in 4/4 (100%) of alveolar but in none of 7 embryonal rhabdomyosarcomas. All 15 (100%) Ewing sarcomas/PNET and 4 clear cell sarcomas (4/4) harbored EWSR1 translocations. SS18 rearrangements were demonstrated in 8/9 (89%) synovial sarcomas. MDM2 amplification was noted in 7/8 (88%) atypical lipomatous tumors/well-differentiated and 3/3 (100%) dedifferentiated liposarcomas, respectively, but not in four pleomorphic liposarcomas. Sensitivities and specificities ranged from 80% to 100% and from 93% to 100%, respectively, with the highest values observed for FOXO1 (100% each). We conclude, therefore, that is possible to accurately predict the STS subtype using a panel of different subtype-specific FISH probes, thereby greatly facilitating the differential diagnosis of these tumors.

Molecular classification of diffuse large B-cell lymphoma (DLBCL) is critical. Numerous methodologies have demonstrated that DLBCL is biologically heterogeneous despite morphological similarities. This underlies the disparate outcomes of treatment response or failure in this common non-Hodgkin lymphoma. This review will summarise historical approaches to lymphoma classifications, current diagnosis of DLBCL, molecular techniques that have primarily been used in the research setting to distinguish and subclassify DLBCL, evaluate contemporary diagnostic methodologies that seek to translate lymphoma biology into clinical practice, and introduce novel diagnostic platforms that may overcome current issues. The review concludes with an overview of key molecular lesions currently identified in DLBCL, all of which are potential targets for drug treatments that may improve survival and cure.

BackgroundAccording to the current World Health Organization Classification of Lymphoid Tumours, follicular lymphoma is subclassified into three grades according to the number of centroblasts. Follicular lymphoma grade 3 can be further divided into types A and B. Almost all available genetic data on grade 3B follicular lymphomas have been generated from tumors with an additional diffuse large B-cell lymphoma component. The purely follicular type of follicular lymphoma grade 3B is a rare neoplasm.Design and MethodsWe performed a detailed immunohistochemical (CD10, IRF4/MUM1, BCL2, Ig light chains) and genetic (translocations of BCL2, BCL6, MYC, IRF4) characterization of the largest series of purely follicular cases of grade 3B follicular lymphoma available to date, comprising 23 tumor samples. We also included 25 typical grade 1 or 2 follicular lymphomas, 9 follicular lymphomas with large centrocytes and/or high proliferation indices (FL/LCC), 12 cases of follicular lymphoma grade 3A, 16 cases of diffuse large B-cell lymphoma/follicular lymphoma grade 3B and 15 follicular lymphomas in which a straightforward distinction between grades 3A and 3B was not possible.ResultsTranslocations affecting BCL2 and BCL6 genes are rare in grade 3B follicular lymphomas (2/23, 9% and 4/23, 17%) when compared with grade 1 or 2 follicular lymphomas (22/25, 88%, P<0.001 and 0/25, P<0.05), FL/LCC (7/9, 78%, P<0.001 and 2/9, 22%), grade 3A follicular lymphomas (7/12, 58%, P<0.01 and 2/12, 17%), unclassified grade 3 follicular lymphomas (6/15, 40% and 2/15, 13%) and diffuse large B-cell lymphoma/follicular lymphoma grade 3B (2/16, 13% and 8/16, 50%, P<0.05). MYC translocations were detected occasionally in FL/LCC, follicular lymphoma grade 3B, and diffuse large B-cell lymphoma/follicular lymphoma grade 3B (13%-22%), but not in grade 1, 2 or 3A follicular lymphomas (P<0.05 when compared with follicular lymphoma grade 3B). Both follicular lymphoma grade 3B and diffuse large B-cell lymphoma/follicular lymphoma grade 3B were enriched in samples with a CD10-IRF4/MUM1(+) immunophenotype (8/19, 42% and 7/16, 44%), with the vast majority of them lacking BCL2 translocations. In contrast, 42/46 grade 1 or 2 follicular lymphomas, FL/LCC and grade 3A follicular lymphomas were CD10(+) (91%) while 0/46 expressed IRF4/MUM1. None of the tumor samples tested with increased IRF4/MUM1-expression harbored a translocation of the IRF4 gene locus.ConclusionsOur results show that grade 3B follicular lymphomas form a distinct category of follicular lymphomas with infrequent BCL2 and BCL6 translocations, while grades 1, 2 and 3A follicular lymphomas and FL/LCC display homogeneous features with frequent BCL2 translocations and a CD10(+)IRF4/MUM1-immunophenotype.

Renal masses are frequently incidentally found on ultrasound. Contrast enhanced computed tomography (CECT) is regarded as the method of choice. Contrast enhanced ultrasound (CEUS) has a high impact for characterisation of hepatic lesions. Its use in renal masses has been less comprehensively studied. Two hundred and one patients referred for surgical treatment of a renal mass, 143 patients fulfilling inclusion criteria (histology and reference method). Baseline ultrasound and CEUS with BR1, histology obtained by surgery (89%) or biopsy (11%). Eighty-eight percent of the patients had renal lesions which were malignant and 12% benign lesions. Eighty percent had renal cell carcinoma (RCC). Seven percent of the lesions were cystic. Two patients were upgraded by CEUS from CECT Bosniak II into CEUS Bosniak III resp. IV. CEUS could predict malignancy with a sensitivity, specificity, positive, negative predictive value and accuracy in 97%, 45%, 91%, 75%, and 90%. The correct staging was diagnosed by CEUS (CECT) in 83% (69%). CEUS was superior to CECT in the staging and characterisation of RCC, also in the subgroup of patients with cystic lesions. CEUS can replace CECT e.g. in patients with allergies or contraindications against CECT. Multicentre studies are necessary to confirm the findings.

We analyzed morphological and immunohistochemical features in 174 aggressive B-cell lymphomas of nodal and extranodal origin. Morphological features included presence or absence of a follicular component and cytologic criteria according to the Kiel classification, whereas immunohistochemical studies included expression of CD10, BCL-2, BCL-6, IRF4/MUM1, HLA-DR, p53, Ki-67 and the assessment of plasmacytoid differentiation. Patients were treated with a CHOP-like regimen. While the presence or absence of either CD10, BCL-6 and IRF4/MUM1 reactivity or plasmacytoid differentiation did not identify particular cytomorphologic or site-specific subtypes, we found that expression of CD10 and BCL-6, and a low reactivity for IRF4/MUM1 were favourable prognostic indicators. In contrast, BCL-2 expression and presence of a monotypic cytoplasmic immunoglobulin expression was associated with an unfavourable prognosis in univariate analyses. Meta-analysis of these data resulted in the development of a cumulative immunohistochemical outcome predictor score (CIOPS) enabling the recognition of four distinct prognostic groups. Multivariate analysis proved this score to be independent of the international prognostic index. Such a cumulative immunohistochemical scoring approach might provide a valuable alternative in the recognition of defined risk types of aggressive B-cell lymphomas.

Objective. To describe three patients with liver lesions mimicking malignant tumours diagnosed finally, using contrast-enhanced ultrasound, as cholangiocellular adenoma (bile duct adenoma). Material and methods. Focal liver lesions found incidentally in three patients. Contrast-enhanced ultrasound was with use of Siemens or Esaote equipment, low MI technique, after an intravenous bolus of 2.4 ml Sonovue (Bracco, Italy). Results. Lesions were 9 mm, 15 mm and 20 mm in diameter and all were enhanced in the arterial phase and hypo-enhanced in the portal venous and late phases, suggesting their malignant nature. In two patients, no primary liver tumour was found, and in the third patient, previously resected for breast cancer, a tissue specimen was considered useful for characterizing tumour receptors for more targeted chemotherapy, the lesion being assumed metastatic in nature. Transcutaneous core biopsies were performed in all three patients. Pathological analysis (including the reference pathology) revealed cholangiocellular adenoma in all of them. Conclusion. Cholangiocellular adenoma is a rare entity and can be a reason for possible false malignant diagnosis using contrast-enhanced ultrasound. Follow-up examinations are recommended.

Follicular lymphoma (FL) is a morphologically and genetically well-characterized B-cell non-Hodgkin lymphoma that can show predominantly follicular, combined follicular and diffuse, or predominantly diffuse growth patterns. Although approximately 85% of FLs harbor the translocation t(14;18)(q32;q21) and consistently display a follicular growth pattern, predominantly diffuse FLs are less well characterized on the phenotypical, molecular, and clinical level. We studied 35 predominantly diffuse FL by immunohistochemistry, classical chromosome banding analysis, fluorescence in situ hybridization (FISH), and gene expression profiling. A total of 28 of 29 analyzable cases lacked t(14;18), and 27 of 29 cases revealed a unifying chromosomal aberration, a deletion in 1p36. Morphologically, 12 FLs were grade 1 and 23 were grade 2, and the immunophenotype with frequent expression of CD10, BCL6, and CD23 was in line with a germinal center B-cell phenotype. The gene expression profiles of 4 predominantly diffuse FLs fell into the spectrum of typical FL, with a unique enrichment of specific gene signatures. Remarkably, patients with diffuse FL frequently presented with low clinical stage and large but localized inguinal tumors. These results suggest that predominantly diffuse FL represent a distinct subtype of t(14;18)-negative nodal FL with a unifying genetic alteration (deletion of 1p36) and characteristic clinical features.