Clinical, pathological, and biological characterization of Richter syndrome developing after ibrutinib treatment for relapsed chronic lymphocytic leukemia.

Richter syndrome, a transformation of chronic lymphocytic leukemia (CLL) into a diffuse large B-cell lymphoma, is a rare complication of patients treated with chemo-immunotherapy. Richter syndrome might be both clonally related or unrelated to the underlying CLL and often showed mutations of the TP53 and NOTCH1 genes. Recently, ibrutinib was approved for patients with relapsed/refractory CLL or for untreated CLL patients with del 17p or TP53 mutation. The clinical picture, pathology, and genetics of Richter transformation after IBR treatment are largely unknown. Here, we report 2 cases of Richter transformation after Ibrutinib treatment. As just reported by previous report, Richter syndrome developing after ibrutinib therapy lacked resistance mutations of the BTK and PLCG2 genes, which are clonally related to the pre-existent CLL phase representing transformation from CLL. Richter syndrome after ibrutinib seems to have some peculiar clinical findings as the bone marrow predilection, severe hypercalcemia, and a more aggressive outcome.

Decreased function of Fas and variations of the perforin gene in adult patients with primary immune thrombocytopenia.

A defective switching off of the immune response is involved in several autoimmune diseases. This switching off involves Fas-mediated apoptosis, perforin-mediated fratricide of activated lymphocytes, and the suppressive activity of regulatory T (Treg) cells. These mechanisms are altered in autoimmune lymphoproliferative syndrome that often displays autoimmune thrombocytopenia. The aim of this research was to evaluate these mechanisms in adult patients with primary immune thrombocytopenia (ITP), compared with healthy controls. The results show that a substantial subgroup of the ITP patients displayed a defective Fas function; most of them displayed decreased Fas expression in T cells activated in vitro. Moreover, ITP patients displayed an increased frequency of rare missense variations of the PRF1 gene and decreased levels of Treg. Immunological analysis showed that levels of Interleukin (IL)10 and IL17 were decreased and marginal zone B cells were increased. Moreover, myeloid and plasmacytoid dendritic cells were decreased in ITP patients. In conclusion, in adult ITP patients, several mechanisms involved in shutting off the immune response are defective and several immunological parameters are dysregulated; these alterations may play a role in the clinical heterogeneity of the disease.

The genetics of nodal marginal zone lymphoma.

Nodal marginal zone lymphoma (NMZL) is a rare, indolent B-cell tumor that is distinguished from splenic marginal zone lymphoma (SMZL) by the different pattern of dissemination. NMZL still lacks distinct markers and remains orphan of specific cancer gene lesions. By combining whole-exome sequencing, targeted sequencing of tumor-related genes, whole-transcriptome sequencing, and high-resolution single nucleotide polymorphism array analysis, we aimed at disclosing the pathways that are molecularly deregulated in NMZL and we compare the molecular profile of NMZL with that of SMZL. These analyses identified a distinctive pattern of nonsilent somatic lesions in NMZL. In 35 NMZL patients, 41 genes were found recurrently affected in ≥3 (9%) cases, including highly prevalent molecular lesions of MLL2 (also known as KMT2D; 34%), PTPRD (20%), NOTCH2 (20%), and KLF2 (17%). Mutations of PTPRD, a receptor-type protein tyrosine phosphatase regulating cell growth, were enriched in NMZL across mature B-cell tumors, functionally caused the loss of the phosphatase activity of PTPRD, and were associated with cell-cycle transcriptional program deregulation and increased proliferation index in NMZL. Although NMZL shared with SMZL a common mutation profile, NMZL harbored PTPRD lesions that were otherwise absent in SMZL. Collectively, these findings provide new insights into the genetics of NMZL, identify PTPRD lesions as a novel marker for this lymphoma across mature B-cell tumors, and support the distinction of NMZL as an independent clinicopathologic entity within the current lymphoma classification.

Molecular prediction of durable remission after first-line fludarabine-cyclophosphamide-rituximab in chronic lymphocytic leukemia.

Fludarabine, cyclophosphamide, and rituximab (FCR) has represented a significant treatment advancement in chronic lymphocytic leukemia (CLL). In the new scenario of targeted agents, there is an increasing interest in identifying patients who gain the maximum benefit from FCR. In this observational multicenter retrospective analysis of 404 CLL patients receiving frontline FCR, the combination of three biomarkers that are widely tested before treatment (IGHV mutation status, 11q deletion and 17p deletion; available in 80% of the study cohort) allowed to identify a very low-risk category of patients carrying mutated IGHV genes but neither 11q or 17p deletion that accounted for 28% of all cases. The majority of very low-risk patients (71%) remained free of progression after treatment and their hazard of relapse decreased after 4 years from FCR. The life expectancy of very low-risk patients (91% at 5 years) was superimposable to that observed in the matched normal general population, indicating that neither the disease nor complications of its treatment affected survival in this favorable CLL group. These findings need a prospective validation and may be helpful for the design of clinical trials aimed at comparing FCR to new targeted treatments of CLL, and, possibly, for optimized disease management.

Mutations of NOTCH1 are an independent predictor of survival in chronic lymphocytic leukemia.

Analysis of the chronic lymphocytic leukemia (CLL) coding genome has recently disclosed that the NOTCH1 proto-oncogene is recurrently mutated at CLL presentation. Here, we assessed the prognostic role of NOTCH1 mutations in CLL. Two series of newly diagnosed CLL were used as training (n = 309) and validation (n = 230) cohorts. NOTCH1 mutations occurred in 11.0% and 11.3% CLL of the training and validation series, respectively. In the training series, NOTCH1 mutations led to a 3.77-fold increase in the hazard of death and to shorter overall survival (OS; P < .001). Multivariate analysis selected NOTCH1 mutations as an independent predictor of OS after controlling for confounding clinical and biologic variables. The independent prognostic value of NOTCH1 mutations was externally confirmed in the validation series. The poor prognosis conferred by NOTCH1 mutations was attributable, at least in part, to shorter treatment-free survival and higher risk of Richter transformation. Although NOTCH1 mutated patients were devoid of TP53 disruption in more than 90% cases in both training and validation series, the OS predicted by NOTCH1 mutations was similar to that of TP53 mutated/deleted CLL. NOTCH1 mutations are an independent predictor of CLL OS, tend to be mutually exclusive with TP53 abnormalities, and identify cases with a dismal prognosis.

Mutations of the SF3B1 splicing factor in chronic lymphocytic leukemia: association with progression and fludarabine-refractoriness.

The genetic lesions identified in chronic lymphocytic leukemia (CLL) do not entirely recapitulate the disease pathogenesis and the development of serious complications, such as chemorefractoriness. While investigating the coding genome of fludarabine-refractory CLL, we observed that mutations of SF3B1, encoding a splicing factor and representing a critical component of the cell spliceosome, were recurrent in 10 of 59 (17%) fludarabine-refractory cases, with a frequency significantly greater than that observed in a consecutive CLL cohort sampled at diagnosis (17/301, 5%; P = .002). Mutations were somatically acquired, were generally represented by missense nucleotide changes, clustered in selected HEAT repeats of the SF3B1 protein, recurrently targeted 3 hotspots (codons 662, 666, and 700), and were predictive of a poor prognosis. In fludarabine-refractory CLL, SF3B1 mutations and TP53 disruption distributed in a mutually exclusive fashion (P = .046). The identification of SF3B1 mutations points to splicing regulation as a novel pathogenetic mechanism of potential clinical relevance in CLL.

Alteration of BIRC3 and multiple other NF-κB pathway genes in splenic marginal zone lymphoma.

Splenic marginal zone lymphoma (SMZL) is one of the few B-cell lymphoma types that remain orphan of molecular lesions in cancer-related genes. Detection of active NF-κB signaling in 14 (58%) of 24 SMZLs prompted the investigation of NF-κB molecular alterations in 101 SMZLs. Mutations and copy number abnormalities of NF-κB genes occurred in 36 (36%) of 101 SMZLs and targeted both canonical (TNFAIP3 and IKBKB) and noncanonical (BIRC3, TRAF3, MAP3K14) NF-κB pathways. Most alterations were mutually exclusive, documenting the existence of multiple independent mechanisms affecting NF-κB in SMZL. BIRC3 inactivation in SMZL recurred because of somatic mutations that disrupted the same RING domain that in extranodal marginal zone lymphoma is removed by the t(11;18) translocation, which points to BIRC3 disruption as a common mechanism across marginal zone B-cell lymphomagenesis. Genetic lesions of NF-κB provide a molecular basis for the pathogenesis of more than 30% of SMZLs and offer a suitable target for NF-κB therapeutic approaches in this lymphoma.

Genomic profiling of Richter's syndrome: recurrent lesions and differences with de novo diffuse large B-cell lymphomas.

Richter's syndrome (RS) represents the transformation of chronic lymphocytic leukaemia (CLL) to aggressive lymphoma and is mostly represented by diffuse large B-cell lymphoma (DLBCL), with a post-germinal centre (GC) phenotype, clonally related to the pre-existing CLL. RS has a very poor prognosis and its pathogenetic mechanisms are poorly understood. In order to gain additional hints in RS pathogenesis, we performed a genome-wide DNA profiling study of 13 RS phases and eight matched CLL phases using the Affymetrix Human Mapping 250K NspI SNP arrays. Individual genomic profiles were heterogeneous, with no individual lesions occurring in more than half of the cases. However, several observations suggest that MYC pathway might be involved in RS. The 13q13.3-qter region containing MIRHG1 (MIR-17-92), a cluster of microRNA interacting with c-MYC, was acquired at the time of transformation. The 13q gain was coupled with the gain of c-MYC and loss of TP53. Translocation of c-MYC was acquired at transformation in a fraction of cases and this event appeared mutually exclusive with gain of MIRHG1. MYCN, a c-MYC homologue, was also recurrently gained. By comparing RS with 48 de novo DLBCL, RS presented a significantly lower prevalence of deletions affecting the PRDM1 and TNFAIP3, genes on 6q, known to be associated with a post-GC phenotype. In conclusion, the genomic profile of RS seems to differ from what observed in de novo DLBCL and in other transformed DLBCL. Genomic lesions occurring in RS are heterogeneous suggesting the existence of different RS subsets, possibly due to different transforming mechanisms. A deregulation of MYC pathway might represent one of the main transformation events in the pathogenesis of a subset of RS clonally related to the previous CLL.

Stereotyped B-cell receptor is an independent risk factor of chronic lymphocytic leukemia transformation to Richter syndrome.

PURPOSE: Few biological prognosticators are useful for prediction of Richter syndrome (RS), representing the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma. Stereotyped B-cell receptors (BCR) may have prognostic effect in CLL progression. We tested the prognostic effect of stereotyped BCR for predicting RS transformation. EXPERIMENTAL DESIGN: The prevalence of stereotyped BCR was compared in RS (n = 69) versus nontransformed CLL (n = 714) by a case-control analysis. Subsequently, the effect of stereotyped BCR at CLL diagnosis on risk of RS transformation was actuarially assessed in a consecutive CLL series (n = 753). RESULTS: RS (n = 69) displayed a higher prevalence of stereotyped BCR (P < 0.001) compared with nontransformed CLL. The actuarial risk of RS transformation was significantly higher in CLL carrying stereotyped BCR (P < 0.001). Among BCR subsets most represented in CLL, subset 8 using IGHV4-39/IGHD6-13/IGHJ5 carried the highest risk of RS transformation [hazard ratio (HR), 24.50; P < 0.001]. Multivariate analysis selected stereotyped BCR (HR, 3.33; P = 0.001) and IGHV4-39 usage (HR, 4.03; P = 0.004) as independent predictors of RS transformation. The combination of IGHV4-39 usage and stereotyped BCR in the same patient identified CLL with a very high risk of RS transformation (5-year risk, 68.7%). The risk carried by stereotyped BCR and IGHV4-39 usage was specific for RS transformation and had no effect on CLL progression without transformation. CONCLUSIONS: Analysis of BCR features may help identify CLL patients at risk of RS. A close monitoring and a careful biopsy policy may help early recognition of RS in CLL patients using stereotyped BCR, particularly if combined with IGHV4-39.

Occult hepatitis B virus infection of peripheral blood mononuclear cells among treatment-naive patients with chronic lymphocytic leukemia.

Recent guidelines emphasise the risk of hepatitis B virus (HBV) reactivation among patients with hematologic malignancies of B lineage, in which HBV has been recently hypothesised to play a pathogenetic role. We aimed to determine the prevalence of occult HBV infection (OBI) of peripheral blood mononuclear cells, defined as detection of sequences from >or=2 HBV genes in subjects lacking hepatitis B surface antigen, among patients with treatment-naive chronic lymphocytic leukemia (CLL). HBV DNA sequences from four HBV genes (S, X, core and pol) were searched for in archival material obtained at diagnosis (N = 173), and from age and sex-matched controls. OBI was observed in 17/173 (10%) patients and 5/173 (3%) controls (OR = 3.6, 95% CI 1.37-9.79, p = 0.014). OBI was not associated with differences on 5-year survival and biological predictors, but patients with CLL with OBI had significantly lower peripheral blood lymphocyte count. After 8 years of observation without treatment, one OBI positive patient with CLL converted into positive HBsAg serology and developed active hepatitis. In conclusion, OBI is significantly more prevalent among patients with CLL than in age and sex-matched controls, and may contribute to the susceptibility of patients with CLL to HBV reactivation, whether exposed or not to biological agents.

Molecular characterization of post-transplant lymphoproliferative disorders of donor origin occurring in liver transplant recipients.

Post-transplant lymphoproliferative disorders (PTLDs) represent a frequent complication of solid organ transplantation. Although most PTLDs arise from recipient lymphoid cells, a considerable fraction of cases may arise from donor B-cells. In an attempt to clarify the histogenesis and pathogenesis of PTLDs derived from donor B-cells, monoclonal PTLDs occurring in liver transplant recipients were chosen as a model to compare donor (D-PTLDs) versus recipient PTLDs (R-PTLDs). The tumour panel included nine D-PTLDs and six R-PTLDs. D-PTLDs were early-onset, EBV-infected lymphoproliferations classified as polymorphic PTLD (P-PTLD; n = 7) or diffuse large B-cell lymphoma (DLBCL; n = 2) with tumour localization confined to the hepatic hilum. All R-PTLDs were late-onset DLBCLs and showed extrahepatic localization. A BCL-6(-)/MUM1(+)/CD138(+/-) phenotype, consistent with a post-germinal centre (GC) stage of pre-terminal B-cell differentiation, was observed in all D-PTLDs and in 2/6 R-PTLDs, whereas a BCL6(+)/MUM1(-)/CD138(-) profile, reminiscent of GC B-cells, was detected in 4/6 R-PTLDs. The presence of somatic IGHV hypermutation was observed in 6/9 D-PTLDs and in 4/6 R-PTLDs, suggesting derivation from antigen-experienced B-cells. IGHV4-39 was the IGHV gene most frequently encountered, being rearranged in 3/9 D-PTLDs. Among IGHV-mutated PTLDs, a mutational profile suggesting antigen stimulation and/or selection was observed in 4/6 D-s and in 2/4 R-PTLDs. The presence of ongoing IGHV mutations was detected in 2/4 D-PTLDs. Aberrant SHM was detected in 10/15 (66.7%) PTLDs, including 6/9 D-PTLDs and 4/6 R-PTLDs. Our findings suggest that (i) D-PTLDs show a clinical presentation distinct from R-PTLDs; (ii) immunophenotypic and genetic features of D-PTLDs are consistent with mature, GC-experienced B-cells; (iii) transformed donor-derived B-cells may experience antigen-driven stimulation and selection, and may acquire genetic lesions during neoplastic expansion in the recipient environment; and (iv) EBV infection and expression of viral oncoproteins may be relevant in the pathogenesis of D-PTLDs.

The NF-{kappa}B negative regulator TNFAIP3 (A20) is inactivated by somatic mutations and genomic deletions in marginal zone lymphomas.

Unique and shared cytogenetic abnormalities have been documented for marginal zone lymphomas (MZLs) arising at different sites. Recently, homozygous deletions of the chromosomal band 6q23, involving the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) gene, a negative regulator of NF-kappaB, were described in ocular adnexal MZL, suggesting a role for A20 as a tumor suppressor in this disease. Here, we investigated inactivation of A20 by DNA mutations or deletions in a panel of extranodal MZL (EMZL), nodal MZL (NMZL), and splenic MZL (SMZL). Inactivating mutations encoding truncated A20 proteins were identified in 6 (19%) of 32 MZLs, including 2 (18%) of 11 EMZLs, 3 (33%) of 9 NMZLs, and 1 (8%) of 12 SMZLs. Two additional unmutated nonsplenic MZLs also showed monoallelic or biallelic A20 deletions by fluorescent in situ hybridization (FISH) and/or SNP-arrays. Thus, A20 inactivation by either somatic mutation and/or deletion represents a common genetic aberration across all MZL subtypes, which may contribute to lymphomagenesis by inducing constitutive NF-kappaB activation.

The prognostic value of TP53 mutations in chronic lymphocytic leukemia is independent of Del17p13: implications for overall survival and chemorefractoriness.

PURPOSE: Del17p13 predicts poor outcome and chemorefractoriness in chronic lymphocytic leukemia (CLL). Conversely, it is unknown whether TP53 mutations carry any prognostic value independent of del17p13. We tested the independent prognostic value of TP53 mutations in CLL. EXPERIMENTAL DESIGN: The study was based on a consecutive series of 308 CLL. DNA sequencing of TP53 exons 2 to 10 and del17p13 interphase fluorescence in situ hybridization were done at CLL diagnosis. Study end points were survival and chemorefractoriness. RESULTS: At diagnosis, TP53 mutations (n = 32) occurred in 31 of 308 (10.0%) patients. Of all CLL showing TP53 disruption by either mutation and/or deletion (n = 44), 10 cases (22.7%) showed TP53 mutations in the absence of del17p13. Multivariate analysis selected TP53 mutations (hazard ratio, 3.20; P = 0.002) as an independent predictor of overall survival after adjustment for del17p13. Also, multivariate analysis selected TP53 mutations (hazard ratio, 3.97; P < 0.001) as an independent predictor of chemorefractoriness after adjustment for del17p13. Compared with cases without TP53 alterations, CLL harboring any type of TP53 disruption (mutation only, del17p13 only, or both mutation and del17p13) uniformly displayed a high prevalence of unfavorable prognosticators and poor outcome. Analysis of sequential CLL samples showed the acquisition of new or additional TP53 alterations at the time of chemorefractoriness. CONCLUSIONS: These data show that (a) TP53 mutations are an independent predictor of short survival and chemorefractoriness, and (b) that CLL presenting with TP53 mutations without del17p13 fare as poorly as CLL carrying del17p13. Because CLL harboring TP53 mutations without del17p13 are currently not recognized by conventional diagnostic strategies, these results may be relevant for a comprehensive prognostic characterization of CLL.

CD49d expression is an independent risk factor of progressive disease in early stage chronic lymphocytic leukemia.

Identification of prognosticators for Binet A chronic lymphocytic leukemia is important for selecting patients with dismal prognosis. We analyzed CD49d expression in 140 consecutive Binet A chronic lymphocytic leukemia. At diagnosis, CD49d >or=30% (54/140, 38.6%) associated with proliferation markers, namely CD38 >or=30% (p=3.9 x 10(-6)), LDH (p=0.007) and beta2-microglobulin (p=0.020). Univariate log-rank analysis identified CD49d >or=30% as a risk factor of treatment free survival (p=8.3 x 10(-5)), time to progression to a more advanced stage (p=4.7 x 10(-4)), and time to lymphocyte doubling (p=0.009). Multivariate analysis selected CD49d >or=30% as an independent treatment free survival predictor after adjustment for biological (HR 2.28; 95% CI 1.71-4.45, p=0.015) and both biological and clinical variables analyzed together (HR 3.33, 95% CI 1.61-6.90, p=0.001). Within Binet A subgroups harboring favorable biological variables (IGHV homology <98%, favorable karyotype, CD38 <30%, ZAP70 <20%) or clinical variables, CD49d >or=30% consistently identified a subset of patients with short treatment free survival. Our observations indicate CD49d >or=30% as a new marker for the initial prognostic assessment of Binet A chronic lymphocytic leukemia.

Molecular analysis of immunoglobulin variable genes in human immunodeficiency virus-related non-Hodgkin's lymphoma reveals implications for disease pathogenesis and histogenesis.

BACKGROUND: Human immunodeficiency virus (HIV)-related non-Hodgkin's lymphomas (HIV-NHL) are heterogeneous and associated with distinct molecular pathways. Analysis of immunoglobulin variable genes (IGV) may provide insights into the pathogenesis and histogenesis of HIV-NHL. DESIGN AND METHODS: IGV rearrangements were amplified from genomic DNA by polymerase chain reaction and directly sequenced in 87 cases of HIV-NHL (17 Burkitt/Burkitt-like lymphomas, 38 diffuse large B-cell lymphomas, and 32 primary central nervous system lymphomas). RESULTS: A skewed IGHV repertoire in specific HIV-NHL clinico-pathological categories was observed. Systemic HIV-diffuse large B-cell lymphomas displayed underrepresentation of the IGHV3 family (11/38, 28.9%; p=0.0047) and, in particular, of the IGHV3-23 gene (0/38; p<0.001). These same cases were also characterized by significant overrepresentation of the IGHV4 family (18/38; 47.4%; p=0.0044) and, in particular, of the IGHV4-34 gene (10/38; 26.3%; p=0.003). HIV-primary central nervous system lymphomas displayed a preferential usage of IGLV6-57, with stereotyped B-cell receptor in two cases. Somatic hypermutation of IGHV genes was detected in 81/87 (93.1%) HIV-NHL. Unmutated cases were restricted to six HIV-primary central nervous system lymphomas with immunoblastic plasmacytoid morphology. A mutational profile suggesting a tendency to maintain antigen binding and antigen selection was observed in more than 50% of the cases of IGV mutated HIV-NHL. CONCLUSIONS: Our data show evidence of a skewed IGHV repertoire in specific HIV-NHL categories and suggest B-cell receptor restriction in some HIV-primary central nervous system lymphomas. The heterogeneous representation of IGHV genes in HIV-NHL may be related to specific pathways of antigen stimulation, or to differences in host's immune dysregulation and lymphoma histogenesis.