Activation of RHOA-VAV1 signaling in angioimmunoblastic T-cell lymphoma.

Somatic G17V RHOA mutations were found in 50-70% of angioimmunoblastic T-cell lymphoma (AITL). The mutant RHOA lacks GTP binding capacity, suggesting defects in the classical RHOA signaling. Here, we discovered the novel function of the G17V RHOA: VAV1 was identified as a G17V RHOA-specific binding partner via high-throughput screening. We found that binding of G17V RHOA to VAV1 augmented its adaptor function through phosphorylation of 174Tyr, resulting in acceleration of T-cell receptor (TCR) signaling. Enrichment of cytokine and chemokine-related pathways was also evident by the expression of G17V RHOA. We further identified VAV1 mutations and a new translocation, VAV1-STAP2, in seven of the 85 RHOA mutation-negative samples (8.2%), whereas none of the 41 RHOA mutation-positive samples exhibited VAV1 mutations. Augmentation of 174Tyr phosphorylation was also demonstrated in VAV1-STAP2. Dasatinib, a multikinase inhibitor, efficiently blocked the accelerated VAV1 phosphorylation and the associating TCR signaling by both G17V RHOA and VAV1-STAP2 expression. Phospho-VAV1 staining was demonstrated in the clinical specimens harboring G17V RHOA and VAV1 mutations at a higher frequency than those without. Our findings indicate that the G17V RHOA-VAV1 axis may provide a new therapeutic target in AITL.

Role of up-front autologous stem-cell transplantation in peripheral T-cell lymphoma for patients in response after induction: an analysis of patients from LYSA centers.

Background: Peripheral T-cell lymphoma (PTCL) remains a therapeutic challenge. Due to the rarity and the heterogeneity of PTCL, no consensus has been achieved regarding even the type of first-line treatment. The benefit of autologous stem-cell transplantation (ASCT) is, therefore, still intensely debated. Patients and methods: In the absence of randomized trials addressing the role of ASCT, we performed a large multicentric retrospective study and used both a multivariate proportional hazard model and a propensity score matching approach to correct for sample selection bias between patients allocated or not to ASCT in intention-to-treat (ITT). Results: Among 527 patients screened from 14 centers in France, Belgium and Portugal, a final cohort of 269 patients ≤65 years old with PTCL-not otherwise specified (NOS) (N = 78, 29%), angioimmunoblastic T-cell lymphoma (AITL) (N = 123, 46%) and anaplastic lymphoma kinase-positive anaplastic large cell lymphoma (ALK-ALCL) (N = 68, 25%) with partial (N = 52, 19%) or complete responses (N = 217, 81%) after induction was identified and information about treatment allocation was carefully collected before therapy initiation from medical records. One hundred and thirty-four patients were allocated to ASCT in ITT and 135 were not. Neither the Cox multivariate model (HR = 1.02; 95% CI: 0.69-1.50 for PFS and HR = 1.08; 95% CI: 0.68-1.69 for OS) nor the propensity score analysis after stringent matching for potential confounding factors (logrank P = 0.90 and 0.66 for PFS and OS, respectively) found a survival advantage in favor of ASCT as a consolidation procedure for patients in response after induction. Subgroup analyses did not reveal any further difference for patients according to response status, stage disease or risk category. Conclusions: The present data do not support the use of ASCT for up-front consolidation for all patients with PTCL-NOS, AITL, or ALK-ALCL with partial or complete response after induction.

BCL2 expression but not MYC and BCL2 coexpression predicts survival in elderly patients with diffuse large B-cell lymphoma independently of cell of origin in the phase 3 LNH03-6B trial.

BACKGROUND: Our aim was to evaluate whether the cell of origin (COO) as defined by the Hans algorithm and MYC/BCL2 coexpression, which are the two main biological risk factors in elderly patients treated with rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine, and prednisolone (R-CHOP), maintain their prognostic value in a large prospective clinical trial. PATIENTS AND METHODS: We evaluated 285 paraffin-embedded samples from patients (60-80 years of age) enrolled in the Lymphoma Study Association trial LNH03-6B who were treated with R-CHOP. We correlated the COO defined by the transcriptome according to the Wright algorithm with that defined by the Hans algorithm in a subset of 62 tumors with available frozen tissue samples. RESULTS: The non-germinal center B-cell-like phenotype according to the Hans algorithm and BCL2 expression (but not MYC and BCL2 coexpression) predicted worse progression-free survival [hazard ratio (HR)=1.78, P = 0.003 and HR = 1.79, P = 0.003, respectively] and overall survival (HR = 1.85, P = 0.005 and HR = 1.67, P = 0.02, respectively) independently of the International Prognostic Index. The correlation between the Hans algorithm and the Wright algorithm was 91%, with an almost perfect concordance according to a kappa test (0.81). CONCLUSIONS: Our results suggest that immunohistochemically defined COO remains a useful tool for predicting prognosis in diffuse large B-cell lymphoma when performed under optimized standardized conditions and that BCL2 expression may help to identify elderly patients at risk for relapse and who could potentially respond to anti-BCL2 targeted agents. In this prospective phase III trial, the coexpression of MYC and BCL2 does not appear to predict worse survival. CLINICAL TRIAL NUMBER: NCT00144755.

DNMT3A(R882H) mutant and Tet2 inactivation cooperate in the deregulation of DNA methylation control to induce lymphoid malignancies in mice.

TEN-ELEVEN-TRANSLOCATION-2 (TET2) and DNA-METHYLTRANSFERASE-3A (DNMT3A), both encoding proteins involved in regulating DNA methylation, are mutated in hematological malignancies affecting both myeloid and lymphoid lineages. We previously reported an association of TET2 and DNMT3A mutations in progenitors of patients with angioimmunoblastic T-cell lymphomas (AITL). Here, we report on the cooperative effect of Tet2 inactivation and DNMT3A mutation affecting arginine 882 (DNMT3A(R882H)) using a murine bone marrow transplantation assay. Five out of eighteen primary recipients developed hematological malignancies with one mouse developing an AITL-like disease, two mice presenting acute myeloid leukemia (AML)-like and two others T-cell acute lymphoblastic leukemia (T-ALL)-like diseases within 6 months following transplantation. Serial transplantations of DNMT3A(R882H) Tet2(-/-) progenitors led to a differentiation bias toward the T-cell compartment, eventually leading to AITL-like disease in 9/12 serially transplanted recipients. Expression profiling suggested that DNMT3A(R882H) Tet2(-/-) T-ALLs resemble those of NOTCH1 mutant. Methylation analysis of DNMT3A(R882H) Tet2(-/-) T-ALLs showed a global increase in DNA methylation affecting tumor suppressor genes and local hypomethylation affecting genes involved in the Notch pathway. Our data confirm the transformation potential of DNMT3A(R882H) Tet2(-/-) progenitors and represent the first cooperative model in mice involving Tet2 inactivation driving lymphoid malignancies.

Prognostic value of baseline total metabolic tumor volume (TMTV0) measured on FDG-PET/CT in patients with peripheral T-cell lymphoma (PTCL).

BACKGROUND: Most peripheral T-cell lymphoma (PTCL) patients have a poor outcome and the identification of prognostic factors at diagnosis is needed. PATIENTS AND METHODS: The prognostic impact of total metabolic tumor volume (TMTV0), measured on baseline [(18)F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography, was evaluated in a retrospective study including 108 PTCL patients (27 PTCL not otherwise specified, 43 angioimmunoblastic T-cell lymphomas and 38 anaplastic large-cell lymphomas). All received anthracycline-based chemotherapy. TMTV0 was computed with the 41% maximum standardized uptake value threshold method and an optimal cut-off point for binary outcomes was determined and compared with others prognostic factors. RESULTS: With a median follow-up of 23 months, 2-year progression-free survival (PFS) was 49% and 2-year overall survival (OS) was 67%. High TMTV0 was significantly associated with a worse prognosis. At 2 years, PFS was 26% in patients with a high TMTV0 (>230 cm(3), n = 53) versus 71% for those with a low TMTV0, [P < 0.0001, hazard ratio (HR) = 4], whereas OS was 50% versus 80%, respectively, (P = 0.0005, HR = 3.1). In multivariate analysis, TMTV0 was the only significant independent parameter for both PFS and OS. TMTV0, combined with PIT, discriminated even better than TMTV0 alone, patients with an adverse outcome (TMTV0 >230 cm(3) and PIT >1, n = 33,) from those with good prognosis (TMTV0 ≤230 cm(3) and PIT ≤1, n = 40): 19% versus 73% 2-year PFS (P < 0.0001) and 43% versus 81% 2-year OS, respectively (P = 0.0002). Thirty-one patients (other TMTV0-PIT combinations) had an intermediate outcome, 50% 2-year PFS and 68% 2-year OS. CONCLUSION: TMTV0 appears as an independent predictor of PTCL outcome. Combined with PIT, it could identify different risk categories at diagnosis and warrants further validation as a prognostic marker.

Breast implant-associated anaplastic large cell lymphoma: two distinct clinicopathological variants with different outcomes.

BACKGROUND: ALK-negative anaplastic large cell lymphoma associated with breast implant (i-ALCL) has been recently recognized as a distinct entity. Among 43 830 lymphomas registered in the French Lymphopath network since 2010, 300 breast lymphomas comprising 25 peripheral T-cell lymphomas (PTCL) were reviewed. Among PTCL, ALK-negative ALCL was the most frequent and all of them were associated with breast implants. PATIENTS AND METHODS: Since 2010, all i-ALCL cases were collected from different institutions through Lymphopath. Immuno-morphologic features, molecular data and clinical outcome of 19 i-ALCLs have been retrospectively analyzed. RESULTS: The median age of the patients was 61 years and the median length between breast implant and i-ALCL was 9 years. Most implants were silicone-filled and textured. Implant removal was performed in 17 out of 19 patients with additional treatment based on mostly CHOP or CHOP-like chemotherapy regimens (n = 10/19) or irradiation (n = 1/19). CHOP alone or ABVD following radiation without implant removal have been given in two patients. The two clinical presentations, i.e. effusion and less frequently tumor mass correlated with distinct histopathologic features: in situ i-ALCL (anaplastic cell proliferation confined to the fibrous capsule) and infiltrative i-ALCL (pleomorphic cells massively infiltrating adjacent tissue with eosinophils and sometimes Reed-Sternberg-like cells mimicking Hodgkin lymphoma). Malignant cells were CD30-positive, showed a variable staining for EMA and were ALK negative. Most cases had a cytotoxic T-cell immunophenotype with variable T-cell antigen loss and pSTAT3 nuclear expression. T-cell receptor genes were clonally rearranged in 13 out of 13 tested cases. After 18 months of median follow-up, the 2-year overall survival for in situ and infiltrative i-ALCL was 100% and 52.5%, respectively. CONCLUSIONS: In situ i-ALCLs have an indolent clinical course and generally remain free of disease after implant removal. However, infiltrative i-ALCLs could have a more aggressive clinical course that might require additional therapy to implant removal.

Early initiation of combined antiretroviral therapy preserves immune function in the gut of HIV-infected patients.

Massive loss of lamina propria CD4(+) T cells, changes in the lymphatic architecture, and altered intestinal epithelial barrier leading to microbial translocation are the common features of HIV-1 infection and are not fully restored under combined antiretroviral therapy (cART). To better understand determinants of gut mucosal restoration, we have performed phenotypic and gene expression analyses of the gut from HIV-infected patients, naive or treated with cART initiated either at the early phase of the primary infection or later during the chronic phase. We found a depletion of T helper type 22 (Th22) and interleukin-17-producing cells in naive patients. These populations, except Th22 cells, were not restored under cART. Regulatory T cells/Th17 ratio was significantly increased in HIV-infected patients and was inversely correlated to the restoration of CD4(+) T cells but not to gut HIV DNA levels. Gene profile analysis of gut mucosal distinguished two groups of patients, which fitted with the timing of cART initiation. In their majority early, but not later treated patients, exhibited conserved intestinal lymphoid structure, epithelial barrier integrity and dendritic cell maturation pathways. Our data demonstrate that early initiation of cART helps to preserve and/or restore lymphoid gut mucosal homeostasis and provide a rationale for initiating cART during the acute phase of HIV infection.

JAK3 deregulation by activating mutations confers invasive growth advantage in extranodal nasal-type natural killer cell lymphoma.

Extranodal, nasal-type natural killer (NK)/T-cell lymphoma (NKCL) is an aggressive malignancy with poor prognosis in which, usually, signal transducer and activator of transcription 3 (STAT3) is constitutively activated and oncogenic. Here, we demonstrate that STAT3 activation mostly results from constitutive Janus kinase (JAK)3 phosphorylation on tyrosine 980, as observed in three of the four tested NKCL cell lines and in 20 of the 23 NKCL tumor samples under study. In one of the cell lines and in 4 of 19 (21%) NKCL primary tumor samples, constitutive JAK3 activation was related to an acquired mutation (A573V or V722I) in the JAK3 pseudokinase domain. We then show that constitutive activation of the JAK3/STAT3 pathway has a major role in NKCL cell growth and survival and in the invasive phenotype. Indeed, NKCL cell growth was slowed down in vitro by targeting JAK3 with chemical inhibitors or small-interfering RNAs. In a human NKCL xenograft mouse model, tumor growth was significantly delayed by the JAK3 inhibitor CP-690550. Altogether, the constitutive activation of JAK3, which can result from JAK3-activating mutations, is a frequent feature of NKCL that deserves to be tested as a therapeutic target.

[Leg ulcer associated with type I cryoglobulinaemia due to incipient B-cell lymphoma]. / Ulcère de jambe lié à une cryoglobulinémie de type 1 révélant un lymphome B « incipiens ¼

BACKGROUND: Skin lesions are frequent in monoclonal cryoglobulinaemia and may be the first sign of B-cell lymphoma, especially multiple myeloma, Waldenström's macroglobulinaemia and B-cell chronic lymphocytic leukaemia. PATIENTS AND METHODS: A 74-year-old woman with no prior medical history presented with necrotic leg ulcer. Skin biopsy showed dermal angiomatosis with numerous PAS+ thromboses, associated with monoclonal intravascular deposits of IgM kappa, indicating monoclonal cryoglobulin, which was confirmed by laboratory tests. Subsequent blood immunophenotyping revealed an inconspicuous circulating monoclonal CD5(+) B-cell population and small B-cell clusters in the bone marrow, while the B-cell count was normal and no lymphadenopathy or splenomegaly were present. Overall, these findings indicated a small B-cell lymphoma, classed as non-MALT marginal zone lymphoma on the WHO classification, at a very early stage of development. The patient was first treated by cyclophosphamide and oral steroids without success. Subsequent administration of six cycles of rituximab, cyclophosphamide, vincristine and prednisone (RCVP) led to remission of her leg ulcer, cryoglobulinaemia and lymphoma. CONCLUSION: Skin biopsies of necrotic ulcers should undergo routine screening for intravascular deposits of type 1 cryoglobulin. Leg ulcers due to monoclonal cryoglobulinaemia may reveal incipient marginal zone B-cell lymphoma at the stage of circulating monoclonal lymphocytosis.

Diffuse large B-cell lymphoma of Waldeyer's ring has distinct clinicopathologic features: a GELA study.

BACKGROUND: Diffuse large B-cell lymphomas (DLBCLs) arising in specific extranodal sites have peculiar clinicopathologic features. PATIENTS AND METHODS: We analyzed a cohort of 187 primary Waldeyer's ring (WR) DLBCLs retrieved from GELA protocols using anthracyclin-based polychemotherapy. RESULTS: Most patients (92%) had stage I-II disease. A germinal center B-cell-like (GCB) immunophenotype was observed in 61%, and BCL2 expression in 55%, of WR DLBCLs. BCL2, BCL6, IRF4 and MYC breakpoints were observed in, respectively, 3 of 42 (7%), 9 of 36 (25%), 2 of 26 (8%) and 4 of 40 (10%) contributive cases. A variable follicular pattern was evidenced in 30 of 68 (44%) large biopsy specimens. The 5-year progression-free survival (PFS) and the overall survival (OS) of 153 WR DLBCL patients with survival information were 69.5% and 77.8%, respectively. The GCB immunophenotype correlated with a better OS (P = 0.0015), while BCL2 expression predicted a worse OS (P = 0.037), an effect overcome by the GCB/non-GCB classification. Compared with matched nodal DLBCLs, WR DLBCLs with no age-adjusted international prognostic index factor disclosed a better 5-year PFS rate (77.5% versus 70.7%; P = 0.03). CONCLUSIONS: WR DLBCLs display distinct clinicopathologic features compared with conventional DLBCLs, with usual localized-stage disease, common follicular features and a high frequency of GCB immunophenotype contrasting with a low rate of BCL2 rearrangements. In addition, they seem to be associated with a better outcome than their nodal counterpart.

Characterization of intratumoral follicular helper T cells in follicular lymphoma: role in the survival of malignant B cells.

Accumulating evidences indicate that the cellular and molecular microenvironment of follicular lymphoma (FL) has a key role in both lymphomagenesis and patient outcome. Malignant FL B cells are found admixed to specific stromal and immune cell subsets, in particular CD4(pos) T cells displaying phenotypic features of follicular helper T cells (T(FH)). The goal of our study was to functionally characterize intratumoral CD4(pos) T cells. We showed that CXCR5(hi)ICOS(hi)CD4(pos) T cells sorted from FL biopsies comprise at least two separate cell populations with distinct genetic and functional features: (i) CD25(pos) follicular regulatory T cells (T(FR)), and (ii) CD25(neg) T(FH) displaying a FL-B cell supportive activity without regulatory functions. Furthermore, despite their strong similarities with tonsil-derived T(FH), purified FL-derived T(FH) displayed a specific gene expression profile including an overexpression of several genes potentially involved directly or indirectly in lymphomagenesis, in particular TNF, LTA, IL4 or CD40LG. Interestingly, we further demonstrated that these two last signals efficiently rescued malignant B cells from spontaneous and rituximab-induced apoptosis. Altogether, our study demonstrates that tumor-infiltrating CD4(pos) T cells are more heterogeneous than previously presumed, and underlines for the first time the crucial role of T(FH) in the complex set of cellular interactions within FL microenvironment.

Follicular lymphoma cell niche: identification of a preeminent IL-4-dependent T(FH)-B cell axis.

Follicular lymphoma (FL) B cells contract tight connections with their microenvironment, which governs the pathogenesis and progression of the disease. Indeed, specific immune response gene signatures, obtained from whole biopsy samples, have been associated with patient survival. In this study, we performed gene expression profiling of purified B cell and non-B cell compartments obtained from FL and reactive lymph nodes. We identified 677 non-redundant genes defining the FL interface and involving 26 FL-specific functional networks. This approach highlighted an interleukin-4 (IL-4)-centered pathway associated with an activation of signal transducer and activator of transcription 6 (STAT6), which favors overexpression of IL-4-target genes. In addition, FL microenvironment was characterized by a strong enrichment in follicular helper T cells (T(FH)), as demonstrated through transcriptomic and flow cytometry analyses. The majority of phospho-STAT6(pos) B cells were located at the vicinity of cells expressing the programmed death 1 (PD-1) T(FH) marker. Moreover, purified FL-derived T(FH), expressed IL4 at very high levels compared with purified tonsil-derived T(FH) or non-T(FH) microenvironment. Altogether, our study demonstrated that tumor-infiltrating T(FH) specifically express functional IL-4 in FL, creating an IL-4-dependent T(FH)-B cell axis. This cross talk could sustain FL pathogenesis and represent a new potential therapeutic target.

The novel immunosuppressive enzyme IL4I1 is expressed by neoplastic cells of several B-cell lymphomas and by tumor-associated macrophages.

We previously reported a strong IL4I1 gene expression in primary mediastinal B-cell lymphoma (PMBL) and recently identified the protein as a secreted L-phenylalanine oxidase, physiologically expressed by myeloid cells, which inhibits T-cell proliferation in vitro. Here, we analyzed the pattern of IL4I1 protein expression in 315 human lymphoid and non-lymphoid malignancies. Besides PMBL, IL4I1 expression in tumors was very frequent. IL4I1 was detected in tumor-associated macrophages from most of the tumors and in neoplastic cells from follicular lymphoma, classic and nodular lymphocyte predominant Hodgkin lymphomas and small lymphocytic lymphoma, three of which are germinal center derived. IL4I1-positive tumor cells were also detected in rare cases of solid cancers, mainly mesothelioma. The enzymatic activity paralleled protein expression, suggesting that IL4I1 is functional in vivo. Depending on the tumor type, IL4I1 may impact on different infiltrating lymphocyte populations with consequences on tumor evolution. In the particular case of follicular lymphoma cells, which are susceptible to antitumor cytotoxic T cells killing but depend on interactions with local T helper cells for survival, a high level of IL4I1 expression seems associated with the absence of bone marrow involvement and a better outcome. These findings plead for an evaluation of IL4I1 as a prognosis factor.

STAT3 transcription factor is constitutively activated and is oncogenic in nasal-type NK/T-cell lymphoma.

Nasal-type natural killer (NK) cell lymphoma is an infrequent aggressive malignant disease with very poor prognosis. We aimed to explore the possible role of the transcription factor STAT3 in the pathophysiology of this malignancy, as it was involved in oncogenesis and chemoresistance. For this, we established and characterized a continuous interleukin 2-dependent NK cell line (MEC04) from a patient with a fatal nasal-type NK-cell lymphoma. Cells harbored poor cytotoxic activity against K562 cells, and spontaneously secreted interferon-gamma, interleukin-10 and vascular-endothelium growth factor in vitro. STAT3 was phosphorylated in Y705 dimerization residue in MEC04 cells and restricted to the nucleus. Y705 STAT3 phosphorylation involved JAK2, as exposure of cells to AG490 inhibitor inhibited Y705 STAT3 phosphorylation. By using recombinant transducible TAT-STAT3-beta (beta isoform), TAT-STAT3Y705F (a STAT3 protein mutated on Y705 residue, which prevents STAT3 dimerization) and peptides inhibiting specifically STAT3 dimerization, we inhibited STAT3 phosphorylation and cell growth, with cell death induction. Finally, STAT3 was phosphorylated in Y705 residue in the nuclei of lymphoma cells in eight/nine patients with nasal-type NK/T-cell lymphoma and in YT, another NK cell line. Our results suggest that STAT3 protein has a major role in the oncogenic process of nasal-type NK-cell lymphomas, and may represent a promising therapeutical target.

Immunohistochemical prognostic markers in diffuse large B-cell lymphoma: validation of tissue microarray as a prerequisite for broad clinical applications (a study from the Lunenburg Lymphoma Biomarker Consortium).

BACKGROUND AND AIMS: The results of class prediction and the determination of prognostic markers in diffuse large B-cell lymphoma (DLBCL) have been variably reported. Apart from biological variations, this may be caused by differences in laboratory techniques, scoring definitions and inter- and intra-observer variation. In this study, an international collaboration of clinical lymphoma research groups has concentrated on validation and standardisation of immunohistochemistry of the currently potentially interesting prognostic markers in DLBCL. METHODS: Sections of a tissue microarray with 36 cases of DLBCL were stained in eight laboratories with antibodies to CD20, CD5, bcl-2, bcl-6, CD10, HLA-DR, MUM-1 and Ki-67 according to local methods. The study was performed in two rounds, firstly focused on the evaluation of laboratory staining variation, and secondly on the scoring variation. RESULTS: Different techniques resulted in highly variable results and poor reproducibility for almost all markers. Reproducibility of the nuclear markers was highly sensitive to technical variations, including immunological enhancement techniques (agreements 34%). With elimination of variation due to staining and uniformly agreed on scoring criteria, significant improvement was seen; however less so for bcl-6 and Ki-67 (agreement 53-58%). Absence of internal controls that preclude scoring, significantly influenced the results for CD10 and bcl-6. CONCLUSION: Semi-quantitative immunohistochemistry for subclassification of DLBCL is feasible, but with varying rates of concordance for different markers and only using optimised techniques and strict scoring criteria. These findings may explain the wide variation in prognostic impact reported in the literature. Harmonisation of techniques and centralised consensus review appears mandatory when using immunohistochemical biomarkers for treatment stratification.

[Gamma-delta T-cell lymphoma: outcome of a hyperactive malarial splenomegaly?]. / Lymphome T gamma-delta: complication possible d'une splénomégalie palustre hyperactive?

We report a gamma-delta T-cell lymphoma, in a male patient having a hyperactive malarial splenomegaly. The immunological disorder caused by chronic antigenic stimulation could be one of the causes leading to the occurrence of such hematologic disease. The prognosis of this type of lymphoma remains poor, partly due to delayed diagnosis. Therefore, it seems appropriate to investigate any atypical hyperactive malarial splenomegaly. In our observation, the macrophagic activation syndrome led us to discover the lymphoma.

L-asparaginase-based treatment of 15 western patients with extranodal NK/T-cell lymphoma and leukemia and a review of the literature.

BACKGROUND: Extranodal natural killer (NK)/T-cell lymphoma, nasal type, and aggressive NK-cell leukemia are highly aggressive diseases with a poor outcome. PATIENTS AND METHODS: We report a multicentric French retrospective study of 15 patients with relapsed, refractory, or disseminated disease, treated with L-asparaginase-containing regimens in seven French centers. Thirteen patients were in relapse and/or refractory and 10 patients were at stage IV. RESULTS: All but two of the patients had an objective response to L-asparaginase-based treatment. Seven patients reached complete remission and only two relapsed. CONCLUSION: These data, although retrospective, confirm the excellent activity of L-asparaginase-containing regimens in refractory extranodal NK/T-cell lymphoma and aggressive NK-cell leukemia. Therefore, L-asparaginase-based regimen should be considered as a salvage treatment, especially for patients with disseminated disease. First-line L-asparaginase combination therapy for extranodal NK/T-cell lymphoma and aggressive NK-cell leukemia should be tested in prospective trials.