Histological verification of positive positron emission tomography findings in the follow-up of patients with mediastinal lymphoma.

Background and Objectives Follow-ups of patients with mediastinal lymphoma are not accurate if they rely on computed tomography (CT). Positron emission tomography (PET) has been suggested to be useful in several lymphoma settings, such as initial staging, evaluation of residual masses after therapy, and assessment of response early in the course of treatment. The aim of this retrospective study was to verify the reliability of positive PET scans of the mediastinum in following up patients wirh mediastinal lymphoma, using histological findings as a comparison. Design and Methods From January 2002 to July 2005, 151 patients with mediastinal lymphoma (57 with Hodgkin's disease [HD] and 94 with aggressive non-Hodgkin's lymphoma [NHL]) were followed-up after the end of front-line treatment. Patients with a positive PET scan of the mediastinum underwent CT scanning and surgical biopsy. Results In 30 (21 HD and 9 NHL) out of 151 patients (20%) a suspicion of lymphoma relapse was raised based on positive mediastinal PET scanning. Histology confirmed this suspicion in 17 (10 HD and 7 NHL) out of 30 patients (57%), whereas either benign (9 fibrosis, 3 sarcoid-like granulomatosis) or unrelated neoplastic conditions (1 thymoma) were demonstrated in the remaining 13 patients (43%). SUVmax was significantly higher among patients who had signs of relapse (17 true positive cases) than among those who stayed in remission (13 false positive cases), the median values being 5.95 (range, 3.5–26.9) and 2.90 (range, 1.4–3.3), respectively ( p =0.01). Interpretation and Conclusions We suggest that a positive PET scan of the mediastinum of a patient being followed-up for a mediastinal lymphoma should not be considered sufficient for diagnostic purposes in view of its lack of discrimination. Histological confirmation can safely be carried out with various biopsy techniques, the choice of which should be made on the basis of the findings of the clinical and imaging studies of the individual case

De novo CD5+ diffuse large B-cell lymphoma: Adverse outcomes with and without stem cell transplantation in a large, multicenter, rituximab treated cohort: CD5 positivity affects DLBCL outcome

De novo CD5+ diffuse large B-cell lymphomas (DLBCL) are a distinct subgroup of DLBCL with poor prognosis. However the role of rituximab-containing therapy and salvage stem cell transplantation in this patients’ population remain to be defined. We retrospectively reviewed clinical features and outcomes of 102 patients with de novo CD5+ DLBCL treated with rituximab-containing therapy at 9 different institutions. By Hans’ criteria, 64 patients had activated B-cell (ABC) subtype, 24 germinal center B-cell (GCB) subtype, and 14 were not evaluated. No patients had a myc translocation. Eighty-three patients were treated with rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP), 7 with rituximab, etoposide, cyclophosphamide, doxorubicin, vincristine, prednisone (R-EPOCH) and 6 with R-CHOP with methotrexate, 3 g/m2. The overall response rate to frontline therapy was 85%. The 3-year progression free survival (PFS) and overall survival (OS) for all patients were 40% and 65%, respectively. The 3-year PFS for ABC- and GCB-subtypes was 34% and 45%, respectively. The 3-year OS for ABC- and GCB-subtypes was 62% and 67%, respectively. The median time to second treatment failure was 3 months and 1 month for ABC- and GCB-subtypes, respectively. Twenty of 28 (71%) transplanted patients with autologous, allogeneic, or both, relapsed. This study confirms the poor prognosis of de novo CD5+ DLBCL in a large multi-center cohort despite initial rituximab-containing chemotherapy and suggests that stem cell transplantation fails to salvage the majority of these patients. Approaches to prevent recurrence and/or novel therapies for relapsed disease are needed for this subgroup of DLBCL patients

XPO1 expression worsens the prognosis of unfavorable DLBCL that can be effectively targeted by selinexor in the absence of mutant p53

Additional file 1. Table S1: Clinicopathologic and molecular characteristics of DLBCL patients with high or low XPO1 expression. Table S2: Significantly differentially expressed genes between XPO1high and XPO1low DLBCL patients with concurrent TP53 mutation and high MYC expression. Figure S1: Biomarker study for XPO1 and selinexor. (A–B) XPO1high expression showed significant adverse prognostic impact in the ABC subtype but not the GCB subtype of DLBCL. (C) XPO1high expression showed a trend of unfavorable prognostic effect on PFS in MYC-rearranged (MYC-R+) DLBCL. (D) XPO1high expression was associated with significantly poorer survival in DLBCL patients with wild type (Wt) TP53. (E) ABC-DLBCL and GCB-DLBCL cells showed similar sensitivity to the cytotoxicity of selinexor. (F) TP53 mutation (Mut-TP53) significantly reduced the anti-lymphoma efficacy of selinexor in HGBCL-DH cells. IC50 values were calculated by GraphPad Prism 8 based on the cell viability data after 72-hour treatment

Dysregulation of PRMT5 in chronic lymphocytic leukemia promotes progression with high risk of Richter's transformation

: Richter's Transformation (RT) is a poorly understood and fatal progression of chronic lymphocytic leukemia (CLL) manifesting histologically as diffuse large B-cell lymphoma. Protein arginine methyltransferase 5 (PRMT5) is implicated in lymphomagenesis, but its role in CLL or RT progression is unknown. We demonstrate herein that tumors uniformly overexpress PRMT5 in patients with progression to RT. Furthermore, mice with B-specific overexpression of hPRMT5 develop a B-lymphoid expansion with increased risk of death, and Eµ-PRMT5/TCL1 double transgenic mice develop a highly aggressive disease with transformation that histologically resembles RT; where large-scale transcriptional profiling identifies oncogenic pathways mediating PRMT5-driven disease progression. Lastly, we report the development of a SAM-competitive PRMT5 inhibitor, PRT382, with exclusive selectivity and optimal in vitro and in vivo activity compared to available PRMT5 inhibitors. Taken together, the discovery that PRMT5 drives oncogenic pathways promoting RT provides a compelling rationale for clinical investigation of PRMT5 inhibitors such as PRT382 in aggressive CLL/RT cases

The Novel Deacetylase Inhibitor AR-42 Demonstrates Pre-Clinical Activity in B-Cell Malignancies In Vitro and In Vivo

While deacetylase (DAC) inhibitors show promise for the treatment of B-cell malignancies, those introduced to date are weak inhibitors of class I and II DACs or potent inhibitors of class I DAC only, and have shown suboptimal activity or unacceptable toxicities. We therefore investigated the novel DAC inhibitor AR-42 to determine its efficacy in B-cell malignancies.In mantle cell lymphoma (JeKo-1), Burkitt's lymphoma (Raji), and acute lymphoblastic leukemia (697) cell lines, the 48-hr IC(50) (50% growth inhibitory concentration) of AR-42 is 0.61 microM or less. In chronic lymphocytic leukemia (CLL) patient cells, the 48-hr LC(50) (concentration lethal to 50%) of AR-42 is 0.76 microM. AR-42 produces dose- and time-dependent acetylation both of histones and tubulin, and induces caspase-dependent apoptosis that is not reduced in the presence of stromal cells. AR-42 also sensitizes CLL cells to TNF-Related Apoptosis Inducing Ligand (TRAIL), potentially through reduction of c-FLIP. AR-42 significantly reduced leukocyte counts and/or prolonged survival in three separate mouse models of B-cell malignancy without evidence of toxicity.Together, these data demonstrate that AR-42 has in vitro and in vivo efficacy at tolerable doses. These results strongly support upcoming phase I testing of AR-42 in B-cell malignancies

Ruolo della proteina arginin-metiltrasferasi-5 (PRMT5) nella linfomagenesi B: implicazioni terapeutiche

Numerosi studi hanno mostrato come i meccanismi epigenetici di regolazione della cromatina svolgano un ruolo centrale nel controllare la trascrizione genica. E’ stato infatti dimostrato che complessi inibitori come SWI/SNF e gli enzimi ad esso associati quali istone deacetilasi (HDAC) e protein arginin-metiltrasferasi (PRMT), siano coinvolti nel controllo della crescita, differenziazione e proliferazione cellulare. Diversi studi hanno mostrato come i meccanismi epigenetici di controllo della trascrizione genica svolgano un ruolo di primo piano nel promuovere la sopravvivenza cellulare in leucemie/linfomi di derivazione dai linfociti B come la leucemia linfatica cronica, il linfoma mantellare ed i linfomi associati al virus di Epstein-Barr (EBV). Tuttavia, molto poco e’ conosciuto circa i meccanismi epigenetici di controllo della trascrizione che divengono operativi e che contribuiscono al processo di trasformazione dei linfociti B. PRMT5 e’ un enzima che di-metila specificamente residui argininici sugli istoni (H) 3 (H3R8) ed 4 (H4R3). PRMT5 ed HDAC lavorano in concerto per reprimere la trascrizione di specifici geni oncosoppressori. In questo progetto sono stati studiati i meccanismi e le conseguenze dell’iperespressione di PRMT5 durante il processo di trasformazione dei linfociti B indotto da EBV, e’ stata dimostrata l’importanza di questo enzima nel processo di trasformazione, e sono stati studiati nuovi metodi per inibirne l’espressione/attivita’. In particolare si e’ dimostrato che l’espressione di PRMT5 e’ ridotta o assente in linfociti B normali (o attivati da stimoli fisiologici) ed elevata in linee cellulari linfoblastoidi immortalizzate o completamente trasformate. Elevati livelli citosolici di PRMT5 sono detectabili dopo 4 giorni dall’infezione di linfociti B normali con EBV, PRMT5 e’ detectabile a livello nucleare, dove esercita la sua funzione repressoria la trascrizione, a partire dal giorno 8. L’utilizzo di specifici small interference RNAs (siRNA) in linee cellulari linfoblastoidi ha permesso di dimostrare la riduzione dell’espressione di PRMT5, la riduzione della metilazione degli istoni target di PRMT5, inibizione della proliferazione cellulare e abbassamento della soglia di sensibilita’ cellulare a stimoli pro-apoptotici. Esperimenti di co-immunoprecipitazione cromatinica hanno permesso di evidenziare che in queste cellule PRMT5 e’ parte di un complesso proteico a funzione inibitoria e che questo complesso si lega alla regione promotrice di specifici geni oncosoppressori quali ST7, GAS e NM23, inibendone la trascrizione. Si e’ inoltre provveduto a sviluppare una categoria di inibitori allosterici di PRMT5: l’attivita’ terapeutica/la specificita’ in vitro e la modalita’ di somministrazione ottimale in modelli murini di linfoma non-Hodgkin, sono in corso di valutazione