Novel insights into the pathogenesis of follicular lymphoma by molecular profiling of localized and systemic disease forms.

Knowledge on the pathogenesis of FL is mainly based on data derived from advanced/systemic stages of FL (sFL) and only small cohorts of localized FL (lFL) have been characterized intensively so far. Comprehensive analysis with profiling of somatic copy number alterations (SCNA) and whole exome sequencing (WES) was performed in 147 lFL and 122 sFL. Putative targets were analyzed for gene and protein expression. Overall, lFL and sFL, as well as BCL2 translocation-positive (BCL2+) and -negative (BCL2-) FL showed overlapping features in SCNA and mutational profiles. Significant differences between lFL and sFL, however, were detected for SCNA frequencies, e.g., in 18q-gains (14% lFL vs. 36% sFL; p = 0.0003). Although rare in lFL, gains in 18q21 were associated with inferior progression-free survival (PFS). The mutational landscape of lFL and sFL included typical genetic lesions. However, ARID1A mutations were significantly more often detected in sFL (29%) compared to lFL (6%, p = 0.0001). In BCL2 + FL mutations in KMT2D, BCL2, ABL2, IGLL5 and ARID1A were enriched, while STAT6 mutations more frequently occurred in BCL2- FL. Although the landscape of lFL and sFL showed overlapping features, molecular profiling revealed novel insights and identified gains in 18q21 as prognostic marker in lFL.

Molecular Cytogenetic Profiling Reveals Similarities and Differences Between Localized Nodal and Systemic Follicular Lymphomas.

Recently, we have developed novel highly promising gene expression (GE) classifiers discriminating localized nodal (LFL) from systemic follicular lymphoma (SFL) with prognostic impact. However, few data are available in LFL especially concerning hotspot genetic alterations that are associated with the pathogenesis and prognosis of SFL. A total of 144 LFL and 527 SFL, enrolled in prospective clinical trials of the German Low Grade Lymphoma Study Group, were analyzed by fluorescence in situ hybridization to detect deletions in chromosomes 1p, 6q, and 17p as well as BCL2 translocations to determine their impact on clinical outcome of LFL patients. The frequency of chromosomal deletions in 1p and 17p was comparable between LFL and SFL, while 6q deletions and BCL2 translocations more frequently occurred in SFL. A higher proportion of 1p deletions was seen in BCL2-translocation-positive LFL, compared with BCL2-translocation-negative LFL. Deletions in chromosomes 1p, 6q, and 17p predicted clinical outcome of patients with SFL in the entire cohort, while only deletions in chromosome 1p retained its negative prognostic impact in R-CHOP-treated SFL. In contrast, no deletions in one of the investigated genetic loci predicted clinical outcome in LFL. Likewise, the presence or absence of BCL2 translocations had no prognostic impact in LFL. Despite representing a genetic portfolio closely resembling SFL, LFL showed some differences in deletion frequencies. BCL2 translocation and 6q deletion frequency differs between LFL and SFL and might contribute to distinct genetic profiles in LFL and SFL.

Tumour cell characteristics and microenvironment composition correspond to clinical presentation in newly diagnosed nodular lymphocyte-predominant Hodgkin lymphoma.

Different studies have characterized the microenvironment and its prognostic impact in classic Hodgkin lymphoma whereas such analyses are pending for nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). We thus investigated characteristics of tumour cells and microenvironment in NLPHL and evaluated possible correlations with the clinical presentation. Lymph node samples from 152 NLPHL patients who had first-line treatment within the randomized German Hodgkin Study Group HD16-HD18 trials were available and analysed with regard to IgD status and nuclear size of the tumour cells as well as presence of PD1-positive follicular T helper cells and CD163-positive macrophages in the microenvironment. While large tumour cell nuclei and high numbers of PD1-positive follicular T helper cells in the microenvironment were more common in patients presenting with early/intermediate stages than in patients with advanced-stage disease (p < 0.0001, unpaired t-test; p = 0.0022, Mann-Whitney test), no differences between risk groups were observed in terms of the IgD status of the tumour cells and the content of CD163-positive macrophages in the microenvironment. PD1-positive follicular T helper cells were present in both cases with typical and variant growth patterns and rosetting around the tumour cells was observed in 96% of patients, indicating an important role of PD1-positive follicular T helper cells in NLPHL.

Histopathological growth patterns in patients with advanced nodular lymphocyte-predominant Hodgkin lymphoma treated within the randomized HD18 study: a report from the German Hodgkin Study Group.

We retrospectively investigated histopathological growth patterns in individuals with advanced nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) treated within the randomized HD18 study. In all, 35/60 patients (58%) presented with atypical growth patterns. Patients with atypical growth patterns more often had stage IV disease (P = 0·0354) and splenic involvement (P = 0·0048) than patients with typical growth patterns; a positive positron emission tomography after two cycles of chemotherapy (PET-2) tended to be more common (P = 0·1078). Five-year progression-free survival [hazard ratio (HR) = 0·86; 95% confidence interval (CI) = 0·49-1·47] and overall survival (HR = 0·85; 95% CI = 0·49-1·51) did not differ between the groups after study treatment with PET-2-guided escalated BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone). Thus, advanced NLPHL is often associated with atypical growth patterns but their prognostic impact is compensated by PET-2-guided escalated BEACOPP.

Comparative analysis of international prognostic indices in gray-zone lymphoma.

Gray-zone lymphoma (GZL) reflects an aggressive B-cell neoplasm with features intermediate between diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma (cHL). The International Prognostic Index (IPI) and its derivatives (R-IPI, NCCN-IPI, and the Hasenclever IPS) have been established for DLBCL or cHL while the most suitable scoring system for GZL remains undetermined. In an exploratory multi-centric cohort of GZL (n = 61), we performed a comparative analysis of prognostic indices with regard to model fit and mutual concordance. The calculation of the corrected Akaike's information criterion (cAIC) and Harrel's concordance index (c-index) for each scoring system identified the NCCN-IPI to harbor the most convincing prognostic capabilities regarding both overall survival (OS) and progression-free survival (PFS) compared to its enhanced derivatives. The current results affirm the clinical utility of the NCCN-IPI and suggest its preferential use in clinical practice in GZL-patients.

Integrative genomic and transcriptomic analysis in plasmablastic lymphoma identifies disruption of key regulatory pathways.

Plasmablastic lymphoma (PBL) represents a clinically heterogeneous subtype of aggressive B-cell non-Hodgkin lymphoma. Targeted-sequencing studies and a single-center whole-exome sequencing (WES) study in HIV-positive patients recently revealed several genes associated with PBL pathogenesis; however, the global mutational landscape and transcriptional profile of PBL remain elusive. To inform on disease-associated mutational drivers, mutational patterns, and perturbed pathways in HIV-positive and HIV-negative PBL, we performed WES and transcriptome sequencing (RNA-sequencing) of 33 PBL tumors. Integrative analysis of somatic mutations and gene expression profiles was performed to acquire insights into the divergent genotype-phenotype correlation in Epstein-Barr virus-positive (EBV+) and EBV- PBL. We describe a significant accumulation of mutations in the JAK signal transducer and transcription activator (OSMR, STAT3, PIM1, and SOCS1), as well as receptor tyrosine-kinase RAS (ERBB3, NRAS, PDGFRB, and NTRK) pathways. We provide further evidence of frequent perturbances of NF-κB signaling (NFKB2 and BTK). Induced pathways, identified by RNA-sequencing, closely resemble the mutational profile regarding alterations accentuated in interleukin-6/JAK/STAT signaling, NF-κB activity, and MYC signaling. Moreover, class I major histocompatibility complex-mediated antigen processing and cell cycle regulation were significantly affected by EBV status. An almost exclusive upregulation of phosphatidylinositol 3-kinase/AKT/mTOR signaling in EBV+ PBL and a significantly induced expression of NTRK3 in concert with recurrent oncogenic mutations in EBV- PBL hint at a specific therapeutically targetable mechanism in PBL subgroups. Our characterization of a mutational and transcriptomic landscape in PBL, distinct from that of diffuse large B-cell lymphoma and multiple myeloma, substantiates the pathobiological independence of PBL in the spectrum of B-cell malignancies and thereby refines the taxonomy for aggressive lymphomas.

Evolutionary clonal trajectories in nodular lymphocyte-predominant Hodgkin lymphoma with high risk of transformation.

The B-cell architecture of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is complex since it is composed of malignant lymphocyte-predominant cells along with a rich B-cell bystander environment. To gain insight into molecular determinants of disease transformation, we studied B-cell evolutionary trajectories in lymphoma tissue from diagnosis to relapse or transformation to non- Hodgkin lymphoma by next-generation sequencing of immunoglobulin heavy chains. Patients with NLPHL that later transformed were older and showed IgD negativity, absence of the characteristic IGHV3/IGHD3/IGHJ6 lymphocyte-predominant rearrangement and high repertoire clonality. We constructed phylogenetic trees within the compartment of the malignant clone to investigate clonal evolution. In all relapsing cases, the lymphocyte-predominant rearrangement was identical at diagnosis and relapse. NLPHL cases with transformation showed more complex trajectories with strong intraclonal diversification. The dominant founder clone in transformations showed clonal evolution if derived from the same cell of origin, or arose from a different cell of origin. Together, our data point to a significant role of antigenic drive in the transformation of NLHPL and identify high B-cell repertoire clonality with dominant intraclonal lymphocyte-predominant cell diversification as a hallmark of transformation. Sequencing of initial paraffin-embedded tissue may therefore be applied diagnostically to identify NLPHL cases with high risk of transformation.

Performance of international prognostic indices in plasmablastic lymphoma: a comparative evaluation.

PURPOSE: Plasmablastic lymphoma (PBL) is a rare and aggressive B-cell malignancy with a heterogenous clinical and prognostic spectrum, determined by multiple factors, including age, HIV- and MYC-status. While there exist several validated scoring systems for diffuse large B-cell lymphoma, which incorporate basic clinical features (age, lactate dehydrogenase, sites of (extranodal) involvement, stage and performance), none of these have been systematically assessed in PBL. METHODS: We determined the (age-adjusted; aa)-International Prognostic Index (IPI), revised IPI (R-IPI), and National Comprehensive Cancer Network IPI (NCCN-IPI) in a comprehensive multi-center cohort (n = 78) of PBL patients. Further, all indices were comparatively investigated for model quality and concordance. RESULTS: Univariate analysis revealed significant prognostic capabilities for all indices, all of which identified a subgroup with favorable outcome. Discriminatory power between patients with less benign prognosis and especially refractory disease exhibited significant variability. Subsequently, stratified models for each risk score were compared employing corrected Akaike's information criterion (cAIC) and Harrel's concordance index (c-index). Here, the NCCN-IPI outperformed both IPI and R-IPI regarding c-index with ambiguous cAIC results, underlining its clinical utility and suggesting it for preferential use in clinical practice. CONCLUSION: Our current observations support the use of the IPI and its enhanced derivatives in PBL patients. There is, however, a distinct requirement for novel prognostic tools to better delineate subgroups at risk for early relapse or refractory disease as well as late relapse. A comprehensive molecular characterization of a clinically annotated cohort of PBL patients is therefore urgently warranted.

Localized- and advanced-stage follicular lymphomas differ in their gene expression profiles.

The genetic background of follicular lymphomas (FLs) diagnosed in advanced clinical stages III/IV, and which are frequently characterized by t(14;18), has been substantially unraveled. Molecular features, as exemplified in the clinicogenetic risk model m7FLIPI, are important tools in risk stratification. In contrast, little information is available concerning localized-stage FL (clinical stages I/II), which accounts for ∼20% of newly diagnosed FL in which the detection rate of t(14;18) is only ∼50%. To investigate the genetic background of localized-stage FL, patient cohorts with advanced-stage FL or localized-stage FL, uniformly treated within phase 3 trials of the German Low-Grade Lymphoma Study Group, were comparatively analyzed. Targeted gene expression (GE) profiling of 184 genes using nCounter technology was performed in 110 localized-stage and 556 advanced-stage FL patients. By penalized Cox regression, a prognostic GE signature could not be identified in patients with advanced-stage FL, consistent with results from global tests and univariate regression. In contrast, it was possible to define robust GE signatures discriminating localized-stage and advanced-stage FL (area under the curve, 0.98) by penalized logistic regression. Of note, 3% of samples harboring an "advanced-stage signature" in the localized-stage cohort exhibited inferior failure-free survival (hazard ratio [HR], 7.1; P = .0003). Likewise, in the advanced-stage cohort, 7% of samples with a "localized-stage signature" had prolonged failure-free survival (HR, 2.3; P = .017) and overall survival (HR, 3.4; P = .072). These data support the concept of a biological difference between localized-stage and advanced-stage FL that might contribute to the superior outcome of localized FL.

The time to relapse correlates with the histopathological growth pattern in nodular lymphocyte predominant Hodgkin lymphoma.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) can present with different histopathological growth patterns. The impact of these histopathological growth patterns on relapse characteristics is unknown. We therefore analyzed paired biopsies obtained at initial diagnosis and relapse from 33 NLPHL patients who had received first-line treatment within German Hodgkin Study Group (GHSG) trial protocols, and from a second cohort of 41 relapsed NLPHL patients who had been treated outside GHSG studies. Among the 33 GHSG patients, 21 patients presented with a typical growth pattern at initial diagnosis, whereas 12 patients had a variant histology. The histopathological growth patterns at initial diagnosis and at relapse were consistent in 67% of cases. A variant histology at initial diagnosis was associated with a shorter median time to lymphoma recurrence (2.8 vs 5.2 years; P = .0219). A similar tendency towards a shorter median time to lymphoma recurrence was observed for patients presenting with a variant histology at relapse, irrespective of the growth pattern at initial diagnosis. Results obtained from the 41 NLPHL patients who had been treated outside GHSG studies were comparable (median time to lymphoma recurrence for variant histology vs typical growth pattern at initial diagnosis: 1.5 vs 7.0 years). In conclusion, the histopathological growth pattern remains consistent at relapse in the majority of NLPHL cases, and has major impact on the time of relapse.

Clinical Impact of the Cell-of-Origin Classification and the MYC/ BCL2 Dual Expresser Status in Diffuse Large B-Cell Lymphoma Treated Within Prospective Clinical Trials of the German High-Grade Non-Hodgkin's Lymphoma Study Group.

Purpose To explore the prognostic impact and interdependence of the cell-of-origin (COO) classification, dual expression (DE) of MYC and BCL2 proteins, and MYC, BCL2, and BCL6 translocations in two prospectively randomized clinical trials of patients with diffuse large B-cell lymphoma (DLBCL). Patients and Methods Overall, 452 formalin-fixed paraffin-embedded samples from two prospective, randomized DLBCL trials (RICOVER-60, prospective, randomized study for patients > 60 years, all IPI groups; and R-MegaCHOEP, prospective, randomized study for patients ≤ 60 years with age-adjusted IPI 2,3) of the German High-Grade Non-Hodgkin Lymphoma Study Group were analyzed with the Lymph2Cx assay for COO classification, with immunohistochemistry for MYC and BCL2, and with fluorescent in situ hybridization for MYC, BCL2, and BCL6 rearrangements. Results COO classification was successful in 414 of 452 samples. No significant differences with respect to COO (activated B-cell [ABC]-like DLBCL v germinal center B-cell [GCB]-like DLBCL) were observed in event-free survival, progression-free survival, and overall survival in patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in the RICOVER-60 trial. Also, no differences with respect to COO were observed in multivariable analyses adjusted for International Prognostic Index factors in event-free survival (hazard ratio [HR] of ABC-like disease v GCB-like disease, 1.0; 95% CI, 0.6 to 1.6; P = .93), progression-free survival (HR, 1.1; 95% CI, 0.6 to 1.8; P = .82), and overall survival (HR, 1.0; 95% CI, 0.6 to 1.8; P = .96). Similar results were observed in the R-MegaCHOEP trial. In patients treated with R-CHOP, DE status was associated with significantly inferior survival compared with nonDE within the GCB, but not within the ABC subgroup. DE status was associated with significantly inferior outcome compared with patients with ABC-like DLBCL without DE (5-year PFS rate, 39% [95% CI,19% to 59%] v 68% [95% CI, 52% to 85%]; P = .03) and compared with patients with GCB-like DLBCL without DE. When data from patients with nonDE were analyzed separately, the outcome of patients in the ABC subgroup was inferior to that of patients in the GCB subgroup (5-year PFS rate, 68% [95% CI, 52% to 85%] v 85% [95% CI, 74% to 96%]; P = .04). Conclusion COO profiling in two prospective randomized DLBCL trials failed to identify prognostic subgroups, whereas dual expression of MYC and BCL2 was predictive of poor survival. Evaluation of prognostic or predictive biomarkers in the management of DLBCL, such as the COO, within prospective clinical trials will be important in the future.

Prognostic Value of Ki-67 Index, Cytology, and Growth Pattern in Mantle-Cell Lymphoma: Results From Randomized Trials of the European Mantle Cell Lymphoma Network.

PURPOSE: Mantle-cell lymphoma (MCL) is a rather aggressive B-cell malignancy whose considerable variability of individual outcome is associated with clinical characteristics (Mantle Cell Lymphoma International Prognostic Index [MIPI]). The Ki-67 index is a strong independent prognostic factor; however, the biologic MIPI (MIPI-b) distinguishes only two groups, which does not appropriately depict the clinical heterogeneity. By using the cohort from the European MCL Younger and MCL Elderly trials, we aimed to evaluate the additional prognostic impact of cytology and growth pattern and to improve risk stratification with the Ki-67 index and MIPI. PATIENTS AND METHODS: Diagnostic tumor biopsies were reviewed by the European Mantle Cell Lymphoma Pathology Panel to determine Ki-67 index by using published guidelines, cytology, and growth pattern. We evaluated prognostic effects for overall survival (OS) by Cox regression. For the cohort used for MIPI-b development (German Low-Grade Lymphoma Study Group [GLSG] 1996 and GLSG2000), we checked whether the equally weighted combination of Ki-67 index (dichotomized at the validated 30% cutoff) and MIPI risk groups was adequate and compared the prognostic power of this modified combination to MIPI and MIPI-b for the MCL Younger/MCL Elderly cohort. RESULTS: The Ki-67 index was assessed in 508 of 832 patients (median age, 62 years). Blastoid cytology was associated with inferior OS independently of MIPI but not independently of the Ki-67 index. Growth pattern was not independently prognostic. The modified combination of the Ki-67 index and MIPI separated four groups with 5-year OS: 85%, 72%, 43%, and 17% (P < .001) and was more discriminative than MIPI and MIPI-b. CONCLUSION: Using the Ki-67 index is superior to using cytology and growth pattern as prognostic factors in MCL. The modified combination of the Ki-67 index and MIPI showed a refined risk stratification, reflecting their strong complementary prognostic effects while integrating the most relevant prognostic factors available in clinical routine.

Hodgkin's lymphoma as a rare variant of Richter's transformation in chronic lymphocytic leukemia: A case report and review of the literature.

Richter's transformation induces an aggressive clinical course in chronic lymphocytic leukemia (CLL). In the majority of cases, Richter's transformation manifests itself as a high-grade B-cell non-Hodgkin's lymphoma (B-NHL). However, other histological types, such as classical Hodgkin lymphoma (cHL), lymphoblastic lymphoma, hairy cell leukemia and high-grade T-cell NHL have been described previously. The present study reports a rare case of CLL with transformation into classical Hodgkin's lymphoma (cHL). The common clonal origin of CLL and cHL was documented by immunoglobulin gene rearrangement analysis performed using multiplex polymerase chain reaction. Following a review of the literature, treatment of secondary Hodgkin's lymphoma is discussed, and prognosis is often poor.

MicroRNA profiling of low-grade and transformed nodal marginal zone lymphoma reveals a similar signature pattern distinct from diffuse large B cell lymphoma.

BACKGROUND/AIMS: As critical post-transcriptional regulators of gene expression, microRNAs are involved in several cellular processes of vital impact including cell growth and apoptosis. Many hematologic malignancies exhibit distinct microRNA signatures. MicroRNA implication in the pathogenesis of nodal marginal zone lymphoma (NMZL), however, remains widely elusive. METHODS: Comprehensive morphologic, immunophenotypic and cytogenetic studies were carried out on a cohort of NMZL (n = 30) incorporating indolent as well as transformed MZL. In addition, microRNA signatures were generated, employing a quantitative real-time polymerase chain reaction approach. These were then compared to signatures from cases of diffuse large B cell lymphoma (DLBCL) alongside reactive lymph node controls. RESULTS: While microRNA signatures of low-grade and transformed NMZL did not differ significantly, several microRNAs were differentially expressed between transformed NMZL and DLBCL, hinting at molecularly distinct mechanisms of lymphomagenesis and indicating the biological disparity of transformed NMZL from DLBCL. CONCLUSION: In the light of the unresolved issue regarding the classification of marginal zone-derived transformed B-cell neoplasms, microRNAs may be a valuable aid in discriminating NMZL from DLBCL.

Histopathological features and their prognostic impact in nodular lymphocyte-predominant Hodgkin lymphoma--a matched pair analysis from the German Hodgkin Study Group (GHSG).

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma entity. We performed a matched-pair analysis to evaluate the prognostic impact of several histopathological features in this distinct Hodgkin lymphoma subtype. Lymph node samples of NLPHL patients were tested for CD15, IgD, phosphorylated STAT6, ICOS and Epstein-Barr virus status of the malignant lymphocyte-predominant cells as well as epithelioid cell clusters and activated T cells in the microenvironment. None of these features was associated with a particular clinical outcome. However, patients presenting with epithelioid cell clusters showed a non-significant trend towards a lower relapse rate, justifying further evaluation of this marker.

The prognostic impact of variant histology in nodular lymphocyte-predominant Hodgkin lymphoma: a report from the German Hodgkin Study Group (GHSG).

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) accounts for approximately 5% of all Hodgkin lymphoma cases. The aim of this study was to evaluate the prognostic implication of histopathologic NLPHL variants. Biopsies of 423 NLPHL patients treated within 9 prospective clinical trials performed by the German Hodgkin Study Group were classified as tumor cell-rich cases (n = 10), typical NLPHL (n = 308), or histopathologic variants (n = 105). Histopathologic variants were characterized by the presence of lymphoma cells outside the B-cell nodules or B-cell depletion of the microenvironment. Compared with typical NLPHL, histopathologic variants were associated with advanced disease (29.5% vs 14.6%, P = .0012) and a higher relapse rate (18.1% vs 6.5% at 5 years, P = .0009). Variant histology represented an independent prognostic factor (odds ratio = 2.955) in a multivariate model of progression/relapse. A prognostic score, including the risk factors variant histopathologic growth pattern, low serum albumin, and male gender, was derived from this model and allowed the definition of 3 distinct risk groups. NLPHL patients presenting with histopathologic variants have a poorer outcome compared with those showing typical histology. The newly developed prognostic score combining histologic and clinical features allows allocating NLPHL patients to defined risk groups.

MYC status in concert with BCL2 and BCL6 expression predicts outcome in diffuse large B-cell lymphoma.

MYC rearrangements occur in 5% to 10% of diffuse large B-cell lymphomas (DLBCL) and confer an increased risk to cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone (CHOP) and rituximab (R)-CHOP treated patients. We investigated the prognostic relevance of MYC-, BCL2- and BCL6-rearrangements and protein expression in a prospective randomized trial. Paraffin-embedded tumor samples from 442 de novo DLBCL treated within the RICOVER study of the German High-Grade Non-Hodgkin Lymphoma Study Group (DSHNHL) were investigated using immunohistochemistry and fluorescence in situ hybridization (FISH) to detect protein expression and breaks of MYC, BCL2, and BCL6. Rearrangements of MYC, BCL2, and BCL6 were detected in 8.8%, 13.5%, and 28.7%, respectively. Protein overexpression of MYC (>40%) was encountered in 31.8% of tumors; 79.6% and 82.8% of tumors expressed BCL2 and BCL6, respectively. MYC translocations, MYChigh, BCL2high, and BCL6low protein expressions were associated with inferior survival. In multivariate Cox regression modeling, protein expression patterns of MYC, BCL2 and BCL6, and MYC rearrangements were predictive of outcome and provided prognostic information independent of the International Prognostic Index (IPI) for overall survival and event-free survival. A combined immunohistochemical or FISH/immunohistochemical score predicts outcome in DLBCL patients independent of the IPI and identifies a subset of 15% of patients with dismal prognosis in the high-risk IPI group following treatment with R-CHOP. Registered at http://www.cancer.gov/clinicaltrials: RICOVER trial of the DSHNHL is NCT 00052936.

Deregulation of a distinct set of microRNAs is associated with transformation of gastritis into MALT lymphoma.

The mechanisms underlying the transformation from chronic Helicobacter pylori gastritis to gastric extranodal marginal zone lymphoma (MALT lymphoma) are poorly understood. This study aims to identify microRNAs that might be involved in the process of neoplastic transformation. We generated microRNA signatures by RT-PCR in 68 gastric biopsy samples representing normal mucosa, gastritis, suspicious lymphoid infiltrates, and overt MALT lymphoma according to Wotherspoon criteria. Analyses revealed a total of 41 microRNAs that were significantly upregulated (n = 33) or downregulated (n = 8) in succession from normal mucosa to gastritis and to MALT lymphoma. While some of these merely reflect the presence of lymphocytes (e.g. miR-566 and miR-212) or H. pylori infection (e.g. miR-155 and let7f), a distinct set of five microRNAs (miR-150, miR-550, miR-124a, miR-518b and miR-539) was shown to be differentially expressed in gastritis as opposed to MALT lymphoma. This differential expression might therefore indicate a central role of these microRNAs in the process of malignant transformation.