Elevated soluble IL-2Rα, IL-8, and MIP-1β levels are associated with inferior outcome and are independent of MIPI score in patients with mantle cell lymphoma

Blockade of CCR1 induces a phenotypic shift in macrophages and triggers a favorable antilymphoma activity

Tumor-associated macrophages (TAMs) within the tumor microenvironment (TME) play an important role in tumor growth and progression. TAMs have been involved in producing immunosuppressive TME via various factors; however, the underlying mechanisms remain unclear in B-cell lymphoma, including mantle cell lymphoma (MCL). We identified that chemokine receptor-1 (CCR1) is highly expressed on monocytes (Mo) and macrophages (MΦ), and CCR1 pharmacological inhibition or CCR1 siRNA abolished lymphoma-mediated Mo/MΦ migration in a chemotaxis assay. The deficiency of host CCR1 (CCR1 KO) was associated with decreased infiltration of peritoneal-MΦ compared with WT-CCR1. Functional studies indicated that the genetic depletion of CCR1 or treatment inhibited protumor MΦ (M2-like) phenotype by decreasing CD206 and IL-10 expression. Moreover, CCR1 depletion reprogrammed MΦ toward an MHCII+/TNFα+ immunogenic phenotype. Mechanistically, protumor MΦ driven-IL-10 provides a positive feedback loop to tumor-CCL3 by regulating the CCL3 promoter via STAT1 signaling. Therapeutic in vivo targeting of CCR1 with CCR1 antagonist BX-471 significantly reduced FC-muMCL1 mouse tumors in the syngeneic MCL model by the depletion of M2-TAMs and increased infiltration of cytotoxic CD8+ T cells. Our study established that CCR1 exerts a pivotal role in macrophage programming, thus shaping protumor TME and lymphoma progression. CCR1 inhibition through CCR1 antagonists may be a promising therapeutic strategy to reprogram macrophages in lymphoma-TME and achieve better clinical outcomes in patients.

Mantle cell lymphoma in 2022-A comprehensive update on molecular pathogenesis, risk stratification, clinical approach, and current and novel treatments

The field of mantle cell lymphoma (MCL) has witnessed remarkable progress due to relentless advances in molecular pathogenesis, prognostication, and newer treatments. MCL consists of a spectrum of clinical subtypes. Rarely, atypical cyclin D1-negative MCL and in situ MCL neoplasia are identified. Prognostication of MCL is further refined by identifying somatic mutations (such as TP53, NSD2, KMT2D), methylation status, chromatin organization pattern, SOX-11 expression, minimal residual disease (MRD), and genomic clusters. Lymphoid tissue microenvironment studies demonstrated the role of B-cell receptor signaling, nuclear factor kappa B (NF-kB), colony-stimulating factor (CSF)-1, the CD70-SOX-11 axis. Molecular mechanism of resistance, mutation dynamics, and pathogenic pathways (B-cell receptor (BCR), oxidative phosphorylation, and MYC) were identified in mediating resistance to various treatments (bruton tyrosine kinase (BTK) inhibitors [ibrutinib, acalabrutinib]. Treatment options range from conventional chemoimmunotherapy and stem cell transplantation (SCT) to targeted therapies against BTK (covalent and noncovalent), Bcl2, ROR1, cellular therapy such as anti-CD19 chimeric antigen receptor therapy (CAR-T), and most recently bispecific antibodies against CD19 and CD20. MCL patients frequently relapse. Complex pathogenesis and the management of patients with progression after treatment with BTK/Bcl2 inhibitors and CAR-T (triple-resistant MCL) remain a challenge. Next-generation clinical trials incorporating newer agents and concurrent translational and molecular investigations are ongoing.

Body mass index and survival of patients with lymphoma

The impact of body mass index (BMI) on survival in lymphoma remains controversial. We leveraged a prospective cohort of lymphoma patients enrolled to SPORE Molecular Epidemiology Resource between 2002 and 2015 to assess the association of BMI before diagnosis, BMI at diagnosis, and BMI change over time with lymphoma-specific survival (LSS). A total of 4009 lymphoma patients (670 diffuse large B-cell lymphoma (DLBCL), 689 follicular lymphoma (FL), 1018 chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), and 1632 other subtypes) were included. Significantly shorter LSS after diagnosis was observed for FL patients who were obese before diagnosis (HR: 3.02, 95%CI: 1.43-6.41, p=.004) and for those with a ≥ 5% increase in BMI from diagnosis to 3-year follow-up (HR: 3.53, 95%CI: 1.22-10.2, p=.020). In contrast, obesity prior to or at the time of diagnosis was not associated with LSS in DLBCL and CLL/SLL. The impact of weight control after diagnosis in FL patient warrants investigation.

Tear cytokine profiles in patients with extranodal marginal zone B-cell lymphoma of the ocular adnexa

OBJECTIVES

To comprehensively analyse the tear cytokine levels of patients with extranodal marginal zone B-cell lymphoma (EMZL) of the ocular adnexa (OA), and the association with clinical characteristics.

METHODS

Tear cytokine concentrations of 21 OA-EMZL patients and 14 age- and sex-matched healthy controls were measured using a 27-multiplex bead analysis on a Luminex system. Tear break-up time, corneal fluorescent staining and other clinical and demographic data were collected as well. The diagnosis of OA-EMZL was established based on the incisional biopsy and histopathology.

RESULTS

The concentrations of interleukin-1 receptor antagonist (IL-1RA) and IL-8, and the ratio of IL-1RA/IL-1β were significantly increased in OA-EMZL tear samples (all P < 0.05), while the levels of three cytokines (FGF-2, IL-2 and IL-4), as well as IL-10/IL-6 ratio were significantly decreased (all P < 0.05). The American Joint Committee on Cancer Tumour stage was significantly associated with tear concentrations of FGF-2 (r = -0.44, P = 0.043), GM-CSF (r = -0.49, P = 0.025) and IL-2 (r = -0.45, P = 0.042), while lacrimal gland lymphoma invasion was related to levels of IL-8 (r = 0.53, P = 0.012), FGF-2 (r = -0.43, P = 0.049) and IL-10/IL-6 ratio (r = -0.48, P = 0.026). Receiver operating characteristic (ROC) curve analysis revealed moderate diagnostic accuracy of these indices in differentiating OA-EMZL from normal eyes (area under ROC: 0.69-0.74).

CONCLUSIONS

Multiple tear cytokines were significantly dysregulated in OA-EMZL patients. These cytokines could potentially serve as diagnostic biomarkers and therapeutic targets in future.

Immune-Checkpoint Inhibitors in B-Cell Lymphoma

Simple Summary

Immune-based treatment strategies, which include immune checkpoint inhibition, have recently become a new frontier for the treatment of B-cell-derived lymphoma. Whereas checkpoint inhibition has given oncologists and patients hope in specific lymphoma subtypes like Hodgkin lymphoma, other entities do not benefit from such promising agents. Understanding the factors that determine the efficacy and safety of checkpoint inhibition in different lymphoma subtypes can lead to improved therapeutic strategies, including combinations with various chemotherapies, biologics and/or different immunologic agents with manageable safety profiles.

Abstract

For years, immunotherapy has been considered a viable and attractive treatment option for patients with cancer. Among the immunotherapy arsenal, the targeting of intratumoral immune cells by immune-checkpoint inhibitory agents has recently revolutionised the treatment of several subtypes of tumours. These approaches, aimed at restoring an effective antitumour immunity, rapidly reached the market thanks to the simultaneous identification of inhibitory signals that dampen an effective antitumor response in a large variety of neoplastic cells and the clinical development of monoclonal antibodies targeting checkpoint receptors. Leading therapies in solid tumours are mainly focused on the cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed death 1 (PD-1) pathways. These approaches have found a promising testing ground in both Hodgkin lymphoma and non-Hodgkin lymphoma, mainly because, in these diseases, the malignant cells interact with the immune system and commonly provide signals that regulate immune function. Although several trials have already demonstrated evidence of therapeutic activity with some checkpoint inhibitors in lymphoma, many of the immunologic lessons learned from solid tumours may not directly translate to lymphoid malignancies. In this sense, the mechanisms of effective antitumor responses are different between the different lymphoma subtypes, while the reasons for this substantial difference remain partially unknown. This review will discuss the current advances of immune-checkpoint blockade therapies in B-cell lymphoma and build a projection of how the field may evolve in the near future. In particular, we will analyse the current strategies being evaluated both preclinically and clinically, with the aim of fostering the use of immune-checkpoint inhibitors in lymphoma, including combination approaches with chemotherapeutics, biological agents and/or different immunologic therapies.

Immune-related protein signature in serum stratify relapsed mantle cell lymphoma patients based on risk

Background

Response to modern treatment strategies, which combine cytotoxic compounds with immune stimulatory agents and targeted treatment is highly variable among MCL patients. Thus, providing prognostic and predictive markers for risk adapted therapy is warranted and molecular information that can help in patient stratification is a necessity. In relapsed MCL, biopsies are rarely available and molecular information from tumor tissue is often lacking. Today, the main tool to access risk is the MCL international prognostic index (MIPI), which does not include detailed biological information of relevance for different treatment options. To enable continuous monitoring of patients, non-invasive companion diagnostic tools are needed which can further reduce cost and patient distress and enable efficient measurements of biological markers.

Methods

We have assessed if serum-based protein profiling can identify immune related proteins that stratify relapsed MCL patients based on risk. Overall, 371 scFv targeting 158 proteins were assessed using an antibody microarray platform. We profiled patients (n = 44) who had been treated within the MCL6-Philemon trial combining targeted and immune-modulatory treatment.

Results

The downstream processing led to the identification of the relapsed immune signature (RIS) consisting of 11 proteins with potential to stratify patients with long and short overall survival (OS). Moreover, in this population, MIPI alone failed to separate high, intermediate and low risk patients, but a combined index based on MIPI together with RIS, MIPI_ris, showed improved performance and significantly stratified all three risk groups based on OS.

Conclusions

Our results show that addition of biological parameters to previous prognostic indices improves patient stratification among patients treated with BTK inhibitor triplet combination, particularly, in the identification of an extreme high risk group.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07678-4.

What Is Responsible for Heterogeneity in Mantle Cell Lymphoma Biology and Outcomes?

Mantle cell lymphoma, despite its common derivation from a t(11;14) error that occurs in a naïve B-cell leading to overexpression of cyclin D1 protein, is characterized by substantial heterogeneity in biology and clinical outcome. Unlike other non-Hodgkin lymphoma types, it is more common in men. Clinical presentation patterns vary from nodal to splenomegaly with leukemia to gastrointestinal involvement. Biological variability is linked to tumor cell proliferation. Increased monocyte/macrophages and their associated proinflammatory cytokines are associated with inferior outcomes. These clues mandate that new treatments should target signal pathways that contribute to these adverse outcomes.

Serum levels of selected cytokines and soluble adhesion molecules in acute myeloid leukemia: Soluble receptor for interleukin-2 predicts overall survival

BACKGROUND

Acute myeloid leukemia (AML) cells are highly resistant to chemotherapeutic drugs. Cytokines and adhesion molecules may contribute to this resistance and affect treatment outcome. The aim of this study was to evaluate the independence and additional prognostic information of baseline serum levels of selected cytokines and soluble adhesion molecules, included in analyses with standard prognostic indicators.

METHODS

We used biochip array technology to measure levels of selected cytokines and soluble adhesion molecules in serum samples of 80 newly diagnosed AML patients. The markers of tumour microenvironment were analysed against high risk karyotype, hyperleucocytosis, higher age, lactic dehydrogenase levels and presence of FLT3-ITD and NPM-1 mutation.

RESULTS

All evaluated analytes were independent of standard prognostic indicators. Fifteen were associated with overall and eight with progression-free survival in univariate analysis. After correction for multiple testing, we identified soluble interleukin-2 receptor-α as an independent indicator of overall survival. Further, the soluble type I TNF-α receptor was close to statistical significance for both overall and progression-free survival.

CONCLUSIONS

Baseline levels of soluble interleukin-2 receptor-α predict overall survival in newly diagnosed AML. The TNF-α type I soluble receptor is a candidate prognostic marker in AML and is worth of further investigation.

Dynamic Changes in Gene Mutational Landscape With Preservation of Core Mutations in Mantle Cell Lymphoma Cells

While studies have identified a number of mutations in mantle cell lymphoma (MCL), the list may still be incomplete and contribution to the pathogenesis remains unclear. We analyzed the mutational landscape of four mantle cell lymphoma biopsies obtained during an 8-year period from the same patient with his normal cells serving as control; we also established a cell line from the final stage of the disease. Numerous mutations with high allelic burden have been identified in all four biopsies. While a large subset of mutations was seen only in individual biopsies, the core of 21 mutations persisted throughout the disease. This mutational core is also maintained in the cell line that also displays DNA-methylation and cytokine secretion profiles of the primary mantle cell lymphoma cells. This cell line is uniquely sensitive to clinically relevant inhibitors of Bruton's Tyrosine Kinase. The response to Bruton Tyrosine Kinase's inhibition is enhanced by inhibitors of CDK4/6 and mTOR. Among the mutations seen in the primary and cultured MCL cells, mutations of three genes are involved in the control of H3K4 methylation: demethylase KDM5C, present already in the early disease, and methyltransferase KMT2D and cofactor BCOR, both of which are seen late in the disease and are novel and predicted to be pathogenic. The presence of these mutations was associated with hypermethylation of H3K4. Restoration of KDM5C expression affected expression of numerous genes involved in cell proliferation, adherence/movement, and invasiveness.

Impact of the soluble interleukin-2 receptor level in the relapsed or refractory phase on the clinical outcome of patients with diffuse large B-cell lymphoma

This study sought to investigate the impact of the soluble interleukin-2 receptor level in the relapsed or refractory phase (r/r sIL-2R) on the clinical outcome in patients with diffuse large B-cell lymphoma (DLBCL). We determined the optimal cutoff value of r/r sIL-2R for disease progression within 6 months from salvage chemotherapy to be 861 U/mL. The high r/r sIL-2R group exhibited a significantly lower survival rate than the low r/r sIL-2R group (1-year event-free survival [EFS], 22.6% vs. 55.7%, p < .001 and 1-year overall survival [OS], 45.9% vs. 75.1%, p < .001). Independent significant correlations were observed between r/r sIL-2R and both inferior 1-year EFS and OS in a multivariate analysis (hazard ratio [HR]: 2.69, 95% CI: 1.61-4.51, p < .001 and HR: 2.99, 95% CI: 1.57-5.70, p < .001). This study demonstrates that r/r sIL-2R could be useful for predicting a poor prognosis in patients with r/r DLBCL.

Recent advances and future directions in mantle cell lymphoma research: report of the 2018 mantle cell lymphoma consortium workshop

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma characterized by the t(11;14) chromosomal translocation. This translocation most often results in overexpression of cyclin D1. MCL is clinically heterogeneous, outcomes are generally poor, and no standard treatment has been established. The recent approvals of ibrutinib and acalabrutinib have provided an additional therapeutic option; however, resistance has emerged as a significant issue and presents the need for more detailed studies of resistance mechanisms. Recent clinical trials have provided new perspectives on the relative efficacy and safety of various approaches for both transplant-eligible and transplant-ineligible patients. Multiple novel strategies are being evaluated in the treatment of MCL, including both targeted agents and cellular immunotherapies. At the Lymphoma Research Foundation's 13th MCL Workshop, researchers gathered to discuss research findings, clinical trial results, and future directions related to MCL, its biology, and its treatment. This report, which includes a summary of each presentation, aims to review recent findings in MCL research and highlight potential areas for future study.

Lymphomas diagnosed in an internal medicine department compared to lymphomas diagnosed in other departments: Clinical and outcome differences

Lymphomas are common malignancies with highly variable clinical presentations and prognosis. Prognostic value of clinical presentation at onset is still questioned. The objective of this study was to compare the disease presentation and the outcome of lymphomas diagnosed in an Internal Medicine Department of a University Hospital to disease presentation and outcome of patients who were referred to the Hematology Department of the same institution by other departments or healthcare facilities.This retrospective monocentric observational study included 37 patients. They were matched to 73 patients, who were referred to the Hematology Department, according to age, histology, and Ann Arbor stage. The demographics, clinical and biological presentations, overall survival, and progression-free survival were compared.Patients diagnosed with lymphoma in the Internal Medicine Department were more likely to be febrile (67.5% vs 21.9%; P < .001) and have higher inflammatory markers (mean C-reactive protein 86.6 vs 56.3 mg/L; P = .02). The median overall survival of these patients was poorer (P < .001), even in the subset of patients treated with standard treatment, and remained shorter in multivariable analysis (P = .002). The specific treatment started earlier (20.2 vs 37.5 days; P = .006), but was more frequently palliative (37.8% vs 19.2%; P = .04). There was no significant difference in median progression-free survival.Lymphomas diagnosed in an Internal Medicine Department had aggressive clinical presentations and a poorer outcome, despite an early start of conventional treatment.

IL-2Rα up-regulation is mediated by latent membrane protein 1 and promotes lymphomagenesis and chemotherapy resistance in natural killer/T-cell lymphoma

BACKGROUND

Natural killer/T-cell lymphoma (NKTCL) is a highly aggressive non-Hodgkin lymphoma often resistant to chemotherapy. Serum level of soluble IL-2 receptor α (IL-2Rα) is elevated in NKTCL patients and correlates significantly with treatment response and survival. In the current study we examined the potential role of IL-2Rα by over-expressing IL-2Rα in representative cell lines.

METHODS

Levels of IL-2Rα were evaluated in the human natural killer cell line NK-92 and the NKTCL cell line SNK-6. Lentiviral vectors were used to express latent membrane protein 1 (LMP1) in NK-92 cells, and IL-2Rα in both NK-92 and SNK-6 cells. The biological effects of these genes on proliferation, apoptosis, cell cycle distribution, and chemosensitivity were analyzed.

RESULTS

Expression of IL-2Rα was significantly higher in SNK-6 cells than in NK-92 cells. Expressing LMP1 in NK-92 cells remarkably up-regulated IL-2Rα levels, whereas selective inhibitorss of the proteins in the MAPK/NF-κB pathway significantly down-regulated IL-2Rα. IL-2Rα overexpression in SNK-6 cells promoted cell proliferation by altering cell cycle distribution, and induced resistance to gemcitabine, doxorubicin, and asparaginase. These effects were reversed by an anti-IL-2Rα antibody.

CONCLUSIONS

Our results suggest that LMP1 activates the MAPK/NF-κB pathway in NKTCL cells, up-regulating IL-2Rα expression. IL-2Rα overexpression promotes growth and chemoresistance in NKTCL, making this interleukin receptor a potential therapeutic target.

Mantle cell lymphoma in the era of precision medicine-diagnosis, biomarkers and therapeutic agents

Despite advances in the development of clinical agents for treating Mantle Cell Lymphoma (MCL), treatment of MCL remains a challenge due to complexity and frequent relapse associated with MCL. The incorporation of conventional and novel diagnostic approaches such as genomic sequencing have helped improve understanding of the pathogenesis of MCL, and have led to development of specific agents targeting signaling pathways that have recently been shown to be involved in MCL. In this review, we first provide a general overview of MCL and then discuss about the role of biomarkers in the pathogenesis, diagnosis, prognosis, and treatment for MCL. We attempt to discuss major biomarkers for MCL and highlight published and ongoing clinical trials in an effort to evaluate the dominant signaling pathways as drugable targets for treating MCL so as to determine the potential combination of drugs for both untreated and relapse/refractory cases. Our analysis indicates that incorporation of biomarkers is crucial for patient stratification and improve diagnosis and predictability of disease outcome thus help us in designing future precision therapies. The evidence indicates that a combination of conventional chemotherapeutic agents and novel drugs designed to target specific dysregulated signaling pathways can provide the effective therapeutic options for both untreated and relapse/refractory MCL.

Associations between elevated pre-treatment serum cytokines and peripheral blood cellular markers of immunosuppression in patients with lymphoma

Higher ratios of the pre-treatment peripheral blood absolute lymphocyte (ALC) to absolute monocyte counts (AMC) are associated with improved outcomes in lymphoma. Conversely, elevated pre-treatment serum cytokines are associated with inferior outcomes. The relationship between pre-treatment serum cytokines and ALC/AMC ratios remains unknown. We studied twelve serum cytokines and the ALC/AMC ratios in 390 patients with untreated diffuse large B-cell, follicular, mantle cell, T-cell, and Hodgkin lymphoma. Different pre-treatment serum cytokine concentrations correlated with ALC, AMC, and ALC/AMC ratios depending on the lymphoma type. In the entire cohort (n = 390) lower ALC/AMC ratios modestly correlated with higher IL-2R (r = -0.36), IL-12 (r = -0.17), IP-10 (r = -0.23), and MIG (r = -0.32) concentrations (p < 0.001). Elevated IL-2R was independently associated with suppressed ALC (OR 2.69, 95% CI 1.77-4.07, p < 0.001), elevated AMC (OR 2.05, 95% CI 1.34-3.14, p < 0.001), and suppressed ALC/AMC ratios (OR 3.51, 95% CI 2.31-5.34, p < 0.001). Both elevated IL-2R (HR 2.27, 95% CI 1.48-3.49, p < 0.001) and suppressed ALC/AMC ratios (HR 1.53, 95% CI 1.03-2.28, p = 0.037) were independently associated with inferior overall survival. These data support the notion that elevated serum cytokines are immunosuppressive and provide further rationale to target the tumor microenvironment for therapeutic benefit.

Predictive value of serum cytokine levels in chronic myeloid leukemia patients

Serum samples taken at diagnosis in 28 chronic myeloid leukemia patients were tested for the presence of 20 cytokines by a magnetic bead-based Bio-plex immunoassay. According to complete cytogenetic remission achieved at 12 months of treatment, patients were divided into groups with either optimal or non-optimal outcome. Patients with increased cytokine levels tended to react optimally to the therapy more frequently than those others. TGF-β3 was a notable exception; its levels were significantly higher in patients with non-optimal outcomes. Further analysis enabled us to define two combinations of cytokine cut-off levels - namely low TGF-β3 and either high IL-8 or high MCP-1-each of which corresponded to therapy outcome better than either Sokal or EUTOS scores.

Comprehensive serum cytokine analysis identifies IL-1RA and soluble IL-2Rα as predictors of event-free survival in T-cell lymphoma

BACKGROUND

T-cell malignancies are heterogeneous in their clinical presentation and pathology, and have a poor prognosis. New biomarkers are needed to predict prognosis and to provide insights into signal pathways used by these cells. The goal of this study was to evaluate pretreatment serum cytokines in patients with newly diagnosed T-cell neoplasms and correlate with clinical outcome.

PATIENTS AND METHODS

We evaluated 30 cytokines in pretreatment serum from 68 untreated patients and 14 normal controls. Significantly elevated cytokines were correlated with patterns of abnormalities, event-free survival (EFS) and overall survival (OS).

RESULTS

Our data demonstrated significantly elevated levels (versus controls) of seven cytokines-epidermal growth factor (EGF), IL-6, IL-12, interferon gamma-induced protein (IP)-10, soluble interleukin (sIL)-2Rα, monokine induced by gamma interferon (MIG), and IL-1RA-in all T-cell neoplasms (P < 0.05). In the angioimmunoblastic subset, all seven cytokines except IP-10 and in the peripheral T-cell lymphoma (TCL)-not otherwise specified subset, only IP-10, sIL-2Rα, MIG, and IL-8 were statistically elevated compared with control. Of these, elevated cytokines all but EGF were predictive of an inferior EFS; IL-1RA, sIL-2Rα, and MIG predicted an inferior OS. In a multivariate analysis, sIL-2Rα [hazard ratio (HR) = 3.95; 95% confidence interval (CI) 1.61-8.38] and IL-1RA (HR = 3.28; 95% CI 1.47-7.29) levels remained independent predictors of inferior EFS. TCL cell lines secreted high levels of sIL-2Rα and expressed the IL-2Rα surface receptor.

CONCLUSIONS

This report describes the cytokines relevant to prognosis in patients with untreated TCL and provides the rationale to include serum IL-1RA and sIL-2Rα as biomarkers in future trials. Inhibition of these cytokines may also be of therapeutic benefit.

The mTORC1 inhibitor everolimus has antitumor activity in vitro and produces tumor responses in patients with relapsed T-cell lymphoma

Everolimus is an oral agent that targets the mammalian target of rapamycin (mTOR) pathway. This study investigated mTOR pathway activation in T-cell lymphoma (TCL) cell lines and assessed antitumor activity in patients with relapsed/refractory TCL in a phase 2 trial. The mTOR pathway was activated in all 6 TCL cell lines tested and everolimus strongly inhibited malignant T-cell proliferation with minimal cytotoxic effects. Everolimus completely inhibited phosphorylation of ribosomal S6, a raptor/mTOR complex 1 (mTORC1) target, without a compensatory activation of the rictor/mTORC2 target Akt (S475). In the clinical trial, 16 patients with relapsed TCL were enrolled and received everolimus 10 mg by mouth daily. Seven patients (44%) had cutaneous (all mycosis fungoides); 4 (25%) had peripheral T cell not otherwise specified; 2 (13%) had anaplastic large cell; and 1 each had extranodal natural killer/T cell, angioimmunoblastic, and precursor T-lymphoblastic leukemia/lymphoma types. The overall response rate was 44% (7/16; 95% confidence interval [CI]: 20% to 70%). The median progression-free survival was 4.1 months (95% CI, 1.5-6.5) and the median overall survival was 10.2 months (95% CI, 2.6-44.3). The median duration of response for the 7 responders was 8.5 months (95% CI, 1.0 to not reached). These studies indicate that everolimus has antitumor activity and provide proof-of-concept that targeting the mTORC1 pathway in TCL is clinically relevant. This trial was registered at www.clinicaltrials.gov as #NCT00436618.