Marco Ladetto

MicroRNAs regulate critical genes associated with multiple myeloma pathogenesis

Progress in understanding the biology of multiple myeloma (MM), a plasma cell malignancy, has been slow. The discovery of microRNAs (miRNAs), a class of small noncoding RNAs targeting multiple mRNAs, has revealed a new level of gene expression regulation. To determine whether miRNAs play a role in the malignant transformation of plasma cells (PCs), we have used both miRNA microarrays and quantitative real time PCR to profile miRNA expression in MM-derived cell lines (n = 49) and CD138+ bone marrow PCs from subjects with MM (n = 16), monoclonal gammopathy of undetermined significance (MGUS) (n = 6), and normal donors (n = 6). We identified overexpression of miR-21, miR-106b∼25 cluster, miR-181a and b in MM and MGUS samples with respect to healthy PCs. Selective up-regulation of miR-32 and miR-17∼92 cluster was identified in MM subjects and cell lines but not in MGUS subjects or healthy PCs. Furthermore, two miRNAs, miR-19a and 19b, that are part of the miR-17∼92 cluster, were shown to down regulate expression of SOCS-1, a gene frequently silenced in MM that plays a critical role as inhibitor of IL-6 growth signaling. We also identified p300-CBP-associated factor, a gene involved in p53 regulation, as a bona fide target of the miR106b∼25 cluster, miR-181a and b, and miR-32. Xenograft studies using human MM cell lines treated with miR-19a and b, and miR-181a and b antagonists resulted in significant suppression of tumor growth in nude mice. In summary, we have described a MM miRNA signature, which includes miRNAs that modulate the expression of proteins critical to myeloma pathogenesis.

Molecular and Clinical Remissions in Multiple Myeloma: Role of Autologous and Allogeneic Transplantation of Hematopoietic Cells

PURPOSE To describe molecular monitoring of minimal residual disease in patients with myeloma who have achieved complete remission (CR) after autologous or allogeneic transplantation of hematopoietic cells. MATERIALS AND METHODS Clonal markers based upon the rearrangement of immunoglobulin heavy-chain genes were generated for each patient and used for polymerase chain reaction (PCR) detection of residual myeloma cells. Fifty-one patients entered the program and 36 achieved CR. After transplantation, molecular monitoring was performed on 29 patients (15 autologous and 14 allogeneic transplants) who had molecular markers. RESULTS Our data show that molecular remissions are rarely achieved (7%) with high-dose chemotherapy followed by single or double autografting. In addition, virtually all peripheral blood progenitor cell and bone marrow samples contained residual myeloma cells, even when sample collection was scheduled after repeated courses of high-dose chemotherapy. All patients autografted with PCR-positive cells remain positive, and eight of 15 have relapsed. Two patients were autografted with PCR-negative cells: one is in clinical and molecular remission, and one relapsed 25 months after the transplant. In the allografting setting, a higher proportion of patients (50%) achieved molecular remission; there were two relapses, one in the PCR-positive group and one in the PCR-negative group. CONCLUSION This is the first large study of molecular remissions in myeloma patients to use a PCR-based approach utilizing patient-specific tumor markers. The sizeable fraction of patients who achieved molecular remission after allografting with peripheral blood progenitor cells represents a promising finding in an incurable disease.

Major Tumor Shrinking and Persistent Molecular Remissions After Consolidation With Bortezomib, Thalidomide, and Dexamethasone in Patients With Autografted Myeloma

PURPOSE We investigated the effect on minimal residual disease, by qualitative and real-time quantitative polymerase chain reaction (RQ-PCR), of a consolidation regimen that included bortezomib, thalidomide, and dexamethasone (VTD) in patients with multiple myeloma (MM) responding to autologous stem-cell transplantation (auto-SCT). PATIENTS AND METHODS Patients achieving at least very good partial response who had an available molecular marker based on the immunoglobulin heavy-chain rearrangement received four courses of treatment every month: four infusions per month of bortezomib at 1.6 mg/m(2), thalidomide at 200 mg/d, and dexamethasone at 20 mg/d on days 1 to 4, 8 to 11, and 15 to 18. Patients were studied with tumor-clone-specific primers by qualitative nested PCR and RQ-PCR. Results Of 39 patients enrolled, 31 received the four VTD courses. Immunofixation complete responses increased from 15% after auto-SCT to 49% after VTD. Molecular remissions (MRs) were 3% after auto-SCT and 18% after VTD. Median time to maximum response was 3.5 months. So far, no patient in MR has relapsed (median follow-up, 42 months). VTD consolidation induced an additional depletion of 4.14 natural logarithms of tumor burden by RQ-PCR. Patients with a tumor load less than the median value after VTD had outcomes better than those who had tumor loads above the median value after VTD (at median follow-up: progression-free survival, 100% v 57%; P < .001). CONCLUSION To the best of our knowledge, this study is the first to document the occurrence of persistent MRs in a proportion of MM patients treated without allogeneic transplantation. Moreover, the major reduction in tumor load recorded by RQ-PCR after VTD suggests that unprecedented levels of tumor cell reduction can be achieved in MM thanks to the new nonchemotherapeutic drugs.

Hodgkin's lymphoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up.

D. A. Eichenauer1, A. Engert1, M. Andre2, M. Federico3, T. Illidge4, M. Hutchings5, & M. Ladetto6 on behalf of the ESMO Guidelines Working Group* First Department of Internal Medicine, University Hospital Cologne and German Hodgkin Study Group (GHSG), Cologne, Germany; CHU Dinant-Godinne, UCL Namur, Yvoir, Belgium; Department of Oncology, Hematology and Respiratory Diseases, University of Modena and Reggio Emilia, Modena, Italy; Institute of Cancer Sciences, University of Manchester, Manchester, UK; Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; Divisione di Ematologia, Azienda Ospedaliera Santi Antonio e Biagio e Cesare Arrigo, Alessandria, Italy

Prospective, multicenter randomized GITMO/IIL trial comparing intensive (R-HDS) versus conventional (CHOP-R) chemoimmunotherapy in high-risk follicular lymphoma at diagnosis: the superior disease control of R-HDS does not translate into an overall survival advantage

In this randomized multicenter study of 136 patients, 6 courses of CHOP (cyclo-phosphamide/doxorubicin/vincristine/prednisone) followed by rituximab (CHOP-R) were compared with rituximab-supplemented high-dose sequential chemotherapy with autografting (R-HDS) to assess the value of intensified chemo-therapy as a first-line treatment for high-risk follicular lymphoma (FL) after the introduction of monoclonal antibodies. The analysis was intention to treat with event-free survival (EFS) as the primary endpoint. Complete remission (CR) was 62% with CHOP-R and 85% with R-HDS (P < .001). At a median follow-up (MFU) of 51 months, the 4-year EFS was 28% and 61%, respectively (P < .001), with no difference in overall survival (OS). Molecular remission (MR) was achieved in 44% of CHOP-R and 80% of R-HDS patients (P < .001), and was the strongest independent outcome predictor. Patients relapsing after CHOP-R underwent salvage R-HDS in 71% of cases. Salvage R-HDS had an 85% CR rate and a 68% 3-year EFS (MFU, 30 months). We conclude that (1) achieving MR is critical for effective disease control, regardless of which treatment is used; (2) R-HDS ensures superior disease control and molecular outcome than CHOP-R, but no OS improvement; and (3) CHOP-R failures have a good outcome after salvage R-HDS, suggesting that relapsed/refractory FL could be the most appropriate setting for R-HDS-like treatments. This trial was registered at www.clinicaltrials.gov as no. NCT00435955.

ESMO Consensus conferences: guidelines on malignant lymphoma. part 2: marginal zone lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma

To complement the existing treatment guidelines for all tumour types, ESMO organizes consensus conferences to focus on specific issues in each type of tumour. In this setting, a consensus conference on the management of lymphoma was held on 18 June 2011 in Lugano, next to the 11th International Conference on Malignant Lymphoma. The conference convened ∼30 experts from all around Europe, and selected six lymphoma entities to be addressed; for each of them, three to five open questions were to be addressed by the experts. For each question, a recommendation should be given by the panel, referring to the strength of the recommendation based on the level of evidence. This consensus report focuses on the three less common lymphoproliferative malignancies: marginal zone lymphoma, mantle cell lymphoma, and peripheral T-cell lymphomas. A first report had focused on diffuse large B-cell lymphoma, follicular lymphoma, and chronic lymphocytic leukaemia.

Interim 18-FDG-PET/CT failed to predict the outcome in diffuse large B-cell lymphoma patients treated at the diagnosis with rituximab-CHOP

Role of interim-PET (I-PET) in diffuse large B-cell Lymphoma (DLBCL) is controversial. To determine predictive value of I-PET on progression-free survival (PFS), we enrolled 88 first-line DLBCL patients treated with 6-8 R-CHOP courses regardless of I-PET. PET/CT were performed at diagnosis, after 2 to 4 courses and at the end of therapy with central reviewing according to visual dichotomous criteria. Results are as follows: I-PET, 72% negative, 28% positive; final-PET (F-PET), 88% negative, 12% positive; clinical complete response 90%. Concordance between clinical response and F-PET negativity was 97% because of 2 false positive. With a median follow-up of 26.2 months, 2-year overall survival and PFS were 91% and 77%, respectively. Two-year PFS for I-PET and F-PET negative versus positive were as follows: I-PET 85% versus 72% (P = .0475); F-PET 83% versus 64% (P < .001). Because of a small number of events, 2 independent bivariate Cox models were tested for PFS. In model 1, F-PET contradicted I-PET (hazard ratio [HR] = 5.03, P = .015 vs 1.27, P = 691); in model 2, F-PET (HR = 4.54) and International propnostic Index score (HR = 5.36, P = .001) remained independent prognostic factors. In conclusion, positive I-PET is not predictive of a worse outcome in DLBCL; larger prospective studies and harmonization of I-PET reading criteria are needed.

Next-generation sequencing and real-time quantitative PCR for minimal residual disease detection in B-cell disorders

In this study, we compared immunoglobulin heavy-chain-gene-based minimal residual disease (MRD) detection by real-time quantitative PCR (RQ-PCR) and next-generation sequencing (NGS) to assess whether NGS could overcome some limitations of RQ-PCR and further increase sensitivity, specificity, accuracy and reproducibility. In total, 378 samples from 55 patients with acute lymphoblastic leukemia (ALL), mantle cell lymphoma (MCL) or multiple myeloma (MM) were investigated for clonotype identification, clonotype identity and comparability of MRD results. Forty-five clonotypes were identified by RQ-PCR and 49 by NGS. Clonotypes identified by both tools were identical or >97% homologous in 96% of cases. Both tools were able to routinely reach a sensitivity level of 1 × E−05. A good correlation of MRD results was observed (R=0.791, P<0.001), with excellent concordance in 79.6% of cases. Few discordant cases were observed across all disease subtypes. NGS showed at least the same level of sensitivity as allele-specific oligonucleotides-PCR, without the need for patient-specific reagents. We conclude that NGS is an effective tool for MRD monitoring in ALL, MCL and MM. Prospective comparative analysis of unselected cases is required to validate the clinical impact of NGS-based MRD assessment.

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.

Gastric marginal zone lymphoma of MALT type: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

E. Zucca1, C. Copie-Bergman2, U. Ricardi3, C. Thieblemont4, M. Raderer5 & M. Ladetto6, on behalf of the ESMO Guidelines Working Group* Lymphoma Unit, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland; APHP, Groupe Henri Mondor-Albert Chenevier, Département de Pathologie, Créteil, France; Department of Oncology, Radiation Oncology Unit, University of Turin, Turin, Italy; Department of Hematology, APHP-Saint-Louis Hospital, University Paris-Diderot, Paris, France; Department of Internal Medicine I and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Division of Hematology, Department of Experimental Medicine and Oncology, University of Turin, San Giovanni Battista Hospital, Turin, Italy