BCL-2 family proteins in peripheral T-cell lymphomas: correlation with tumour apoptosis and proliferation

Sensitivity of canine hematological cancers to BH3 mimetics

BACKGROUND

Inhibition of antiapoptotic B-cell lymphoma 2 (BCL2) proteins by small molecule Bcl-2 homology 3 (BH3) mimetics causes rapid induction of apoptosis of human hematological cancers in vitro and in vivo.

OBJECTIVES

Assess in vitro sensitivity of non-neoplastic lymphocytes and primary hematological cancer cells from dogs to venetoclax (VEN) or the dual BCL2/ B-cell lymphoma-extra-large (BCLxL) inhibitor, navitoclax (NAV), and evaluate the association between BCL2 protein expression and VEN sensitivity.

ANIMALS

Nine client-owned dogs without cancer and 18 client-owned dogs with hematological cancer.

METHODS

Prospective, nonrandomized noncontrolled study. Lymphocytes isolated from peripheral blood, lymph node, or bone marrow from dogs were incubated with BH3 mimetics for 24 hours. Viable cells were counted using flow cytometry and half maximal effective concentration (EC₅₀ ) was calculated. BCL2 protein from whole cell lysates was assessed via immunoblots.

RESULTS

Nodal B and T lymphocytes were more sensitive to VEN than circulating lymphocytes (P = .02). Neoplastic T lymphocytes were sensitive to VEN (mean EC₅₀  ± SD = 0.023 ± 0.018 μM), whereas most non-indolent B cell cancers were resistant to killing by VEN (mean EC₅₀  ± SD = 288 ± 700 μM). Unclassified leukemias showed variable sensitivity to VEN (mean EC₅₀  ± SD = 0.49 ± 0.66 μM). Detection of BCL2 protein was not associated with VEN sensitivity.

CONCLUSION AND CLINICAL IMPORTANCE

Neoplastic canine T lymphocytes are sensitive to VEN in vitro. Quantification of BCL2 protein alone is insufficient to predict sensitivity to VEN.

B-cell lymphoma-2 (BCL2) downregulation is a useful feature -supporting a neoplastic phenotype in mature T-cell lymphomas

Normal T-cells express high levels of BCL2 protein, data regarding BCL2 expression status and its diagnostic utility in T-cell lymphoma is scarce. We evaluated BCL2 expression in a series of mature T-cell lymphoproliferations including indolent and more recently recognized entities (follicular helper T-cell (TFH) lymphomas). Sixty-six neoplastic biopsies (60 patients) representing mature nodal, extranodal and leukemia T-cell neoplasms were collected from three institutes (2 US and 1 Japan) and were compared with reactive T-cells in 8 benign tissues/blood and 9 T-cell rich B-cell proliferations. BCL2 immunostaining was performed and scored based on intensity weighted H-score (0-300). Next generation sequencing (5 cases), BCL2 gene sequencing, and real time-PCR (3 cases) were conducted. Association of H-score with overall survival (using proportional hazards modeling) was assessed in non-leukemic T-cell lymphoproliferations (TCL). Most TCLs showed significantly downregulated median BCL2 H-score (125, range 18-300) with the exception of T-cell prolymphocytic leukemia (T-PLL) and hepatosplenic T-cell lymphoma (HSTL) both of which showed uniform strong retention of BCL2 as did the 8 reactive tissues (median H-score 280; p=0.000). Notably all TFH lymphoma CD4 neoplastic T-cells, subcutaneous panniculitis-like T-cell lymphoma (SPTCL) CD8 adipocyte-rimming T-cells and T-cell large lymphocyte leukemia (T-LGLL) with pathogenic STAT5B and TP53 mutation showed BCL2 downregulation. No BCL2 mutations were observed by NGS or sequencing with decreased BCL2 mRNA transcripts by real-time PCR. BCL2 downregulation is pervasive among many T-cell lymphoproliferations and unrelated to any mutations. There is utility for BCL2 immunostaining in some challenging situations as discussed in manuscript.

Novel Treatments for Pediatric Relapsed or Refractory Acute B-Cell Lineage Lymphoblastic Leukemia: Precision Medicine Era

With the markedly increased cure rate for children with newly diagnosed pediatric B-cell acute lymphoblastic leukemia (B-ALL), relapse and refractory B-ALL (R/R B-ALL) remain the primary cause of death worldwide due to the limitations of multidrug chemotherapy. As we now have a more profound understanding of R/R ALL, including the mechanism of recurrence and drug resistance, prognostic indicators, genotypic changes and so on, we can use newly emerging technologies to identify operational molecular targets and find sensitive drugs for individualized treatment. In addition, more promising and innovative immunotherapies and molecular targeted drugs that are expected to kill leukemic cells more effectively while maintaining low toxicity to achieve minimal residual disease (MRD) negativity and better bridge hematopoietic stem cell transplantation (HSCT) have also been widely developed. To date, the prognosis of pediatric patients with R/R B-ALL has been enhanced markedly thanks to the development of novel drugs. This article reviews the new advancements of several promising strategies for pediatric R/R B-ALL.

Venetoclax Shows Low Therapeutic Activity in BCL2-Positive Relapsed/Refractory Peripheral T-Cell Lymphoma: A Phase 2 Study of the Fondazione Italiana Linfomi

Patients with relapsed/refractory (R/R) peripheral T-cell lymphoma (PTCL) have a poor prognosis, with an expected survival of less than 1 year using standard salvage therapies. Recent advances in our understanding of the biology of PTCL have led to identifying B-Cell Lymphoma 2 (BCL2) protein as a potential therapeutic target. BLC2 inhibitor venetoclax was investigated in a prospective phase II trial in patients with BCL2-positive R/R PTCL after at least one previous standard line of treatment (NCT03552692). Venetoclax given alone at a dosage of 800 mg/day resulted in one complete response (CR) and two stable diseases (SDs) among 17 enrolled patients. The majority of patients (88.2%) interrupted the treatment due to disease progression. No relationship with BCL2 expression was documented. At a median follow-up of 8 months, two patients are currently still on treatment (one CR and one SD). No case of tumor lysis syndrome was registered. Therefore, venetoclax monotherapy shows activity in a minority of patients whose biological characteristics have not yet been identified.

Clinical Trial Registration

www.clinicaltrials.gov (NCT03552692, EudraCT number 2017-004630-29).

Peripheral T-Cell Lymphoma, Not Otherwise Specified: Clinical Manifestations, Diagnosis, and Future Treatment

Peripheral T-cell lymphoma, not otherwise specified (PTCL_NOS) corresponds to about one fourth of mature T-cell tumors, which overall represent 10-12% of all lymphoid malignancies. This category comprises all T-cell neoplasms, which do not correspond to any of the distinct entities listed in the WHO (World Health Organization) Classification of Tumours of Haematopoietic and Lymphoid Tissues. In spite of the extreme variability of morphologic features and phenotypic profiles, gene expression profiling (GEP) studies have shown a signature that is distinct from that of all remaining PTCLs. GEP has also allowed the identification of subtypes provided with prognostic relevance. Conversely to GEP, next-generation sequencing (NGS) has so far been applied to a limited number of cases, providing some hints to better understand the pathobiology of PTCL_NOS. Although several pieces of information have emerged from pathological studies, PTCL_NOS still remains a tumor with a dismal prognosis. The usage of CHOEP (cyclophosphamide, doxorubicin, vincristine, prednisone, etoposide) followed by autologous stem cell transplantation may represent the best option, by curing about 50% of the patients whom such an approach can be applied to. Many new drugs have been proposed without achieving the expected results. Thus, the optimal treatment of PTCL_NOS remains unidentified.

Expression of BCL2 alternative proteins and association with outcome in CLL patients treated with venetoclax

Venetoclax, a BCL-2 inhibitor, is highly effective for the treatment of patients with chronic lymphocytic leukemia (CLL) and dependence on alternative proteins may result in resistance to BCL-2 inhibition. Patients with CLL treated with venetoclax as monotherapy at MD Anderson Cancer Center between 05/2012 and 01/2016 were included and pretreatment bone marrow was analyzed by immunohistochemistry (IHC) for BCL-W, BCL-XL, BCL2-A1 and MCL-1. Twenty-seven patients were included. BCL-W + and BCL-2A1+ was found in 15% and 7% of the patients, respectively. Both BCL-XL and MCL-1 were negative in all samples. A higher CR and longer PFS rates were observed in patients with BCL-W+ (p = .60, p = .46), BCL-2A1+ (p = .60, p = .29), and either BCL-W + or BCL-2A1+ (p = .33, p = .20), though not statistically significant. Pretreatment IHC expression of BCL-2 alternative proteins does not predict response to venetoclax in CLL, but may be a surrogate for an indolent biology. Sensitive techniques are needed to explore anti-apoptotic pathways.

Nimbolide induces cell death in T lymphoma cells: Implication of altered apoptosis and glucose metabolism

Nimbolide is a tetranortriterpenoid derived from the leaves and flowers of Azadirachta indica (Neem). It exhibits anticancer activity against a variety of cancers by modulating various crucial features, including cell proliferation, apoptosis, and invasion and metastasis. More importantly, the cytotoxic effect of nimbolide has also been observed against T cell lymphoma, but the underlying mechanisms are still unexplored. So far, no study has been conducted to observe the effect of nimbolide on cancer cell metabolism. Therefore, the present investigation was designed to explore the molecular mechanisms of the antitumor potential of nimbolide against T cell lymphoma, a neoplastic disorder of thymic origin. In addition, we also unraveled the anti-glycolytic activity of nimbolide against T lymphoma cells with possible molecular mechanisms. Our results showed the cytotoxic action of nimbolide against three different cell lines of T cell lymphoma, namely Dalton's lymphoma, HuT-78, and J6. Nimbolide-induced apoptosis in T lymphoma cells by altering the level of reactive oxygen species, p53, Bcl2, Bax, and cytochrome c, with subsequent cleavage of caspase 3. Remarkably, nimbolide inhibited the expression of hypoxia-inducible factor-1α, glucose transporter 3, hexokinase II, and pyruvate dehydrogenase kinase 1, which led to the suppression of glycolysis with concomitant activation of oxidative phosphorylation. Hence, the results of the present investigation demonstrate that nimbolide exerts tumoricidal activity against T lymphoma cells via augmentation of apoptosis and reversal of altered cell metabolism. Thus, the present study provides a new insight for the therapeutic utilization of nimbolide against T cell lymphoma.

Bcl-2 Is a Therapeutic Target for Hypodiploid B-Lineage Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. The highest rates of treatment failure occur in specific genetic subsets of ALL, including hypodiploid B-cell ALL (B-ALL), for which effective alternative therapies to current intensive chemotherapy treatments have yet to be developed. Here, we integrated biochemical and genomic profiling with functional drug assays to select effective agents with therapeutic potential against hypodiploid B-ALL. ABT-199, a selective Bcl-2 inhibitor, was effective in reducing leukemic burden in vitro and in vivo in patient-derived xenograft models of hypodiploid B-ALL. Daily oral treatment with ABT-199 significantly increased survival in xenografted mice. The unexpected efficacy of ABT-199 observed in hypodiploid leukemias lacking BIM expression (the major reported mediator of ABT-199-induced apoptosis) led us to investigate the mechanism of action of ABT-199 in the absence of BIM. Treatment with ABT-199 elicited responses in a dose-dependent manner, from cell-cycle arrest at low nanomolar concentrations to cell death at concentrations above 100 nmol/L. Collectively, these results demonstrate the efficacy of Bcl-2 inhibition and potential therapeutic strategy in hypodiploid B-ALL. SIGNIFICANCE: These results demonstrate the efficacy of ABT-199 in vivo and provide encouraging preclinical data of Bcl-2 as a potential target for the treatment of hypodiploid B-ALL.

Biomarker-driven strategy for MCL1 inhibition in T-cell lymphomas

There is a pressing need for more effective therapies to treat patients with T-cell lymphomas (TCLs), including first-line approaches that increase the response rate to cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP) chemotherapy. We characterized the mitochondrial apoptosis pathway in cell lines and patient-derived xenograft (PDX) models of TCL and assessed the in vitro efficacy of BH3 mimetics, including the BCL2 inhibitor venetoclax, the BCL2/BCL-xL inhibitor navitoclax, and the novel MCL1 inhibitor AZD5991. The abundance of antiapoptotic BCL2 family members based on immunoblotting or RNA transcript levels correlated poorly with the activity of BH3 mimetics. In contrast, the functional approach BH3 profiling reliably predicted sensitivity to BH3 mimetics in vitro and in vivo. We used BH3 profiling to select TCL PDX that were dependent on MCL1. Mice xenografted with these PDX and treated with AZD5991 had markedly improved survival. The combination of AZD5991 and CHOP achieved synergy based on survival improvement beyond a mathematical "sum of benefits" model. Thus, MCL1 inhibition is a promising strategy as both a single agent and in combination with chemotherapy for patients with TCL and functional dependence on MCL1.

Groucho related gene 5 (GRG5) is involved in embryonic and neural stem cell state decisions

Groucho related gene 5 (GRG5) is a multifunctional protein that has been implicated in late embryonic and postnatal mouse development. Here, we describe a previously unknown role of GRG5 in early developmental stages by analyzing its function in stem cell fate decisions. By both loss and gain of function approaches we demonstrate that ablation of GRG5 deregulates the Embryonic Stem Cell (ESC) pluripotent state whereas its overexpression leads to enhanced self-renewal and acquisition of cancer cell-like properties. The malignant characteristics of teratomas generated by ESCs that overexpress GRG5 reveal its pro-oncogenic potential. Furthermore, transcriptomic analysis and cell differentiation approaches underline GRG5 as a multifaceted signaling regulator that represses mesendodermal-related genes. When ESCs exit pluripotency, GRG5 promotes neuroectodermal specification via Wnt and BMP signaling suppression. Moreover, GRG5 promotes the neuronal reprogramming of fibroblasts and maintains the self-renewal of Neural Stem Cells (NSCs) by sustaining the activity of Notch/Hes and Stat3 signaling pathways. In summary, our results demonstrate that GRG5 has pleiotropic roles in stem cell biology functioning as a stemness factor and a neural fate specifier.

Transformation of mouse T cells requires MYC and AKT activity in conjunction with inhibition of intrinsic apoptosis

Peripheral T-cell lymphoma is an aggressive non-Hodgkin's lymphoma characterized by excessive proliferation of transformed mature T cells. The number and nature of genetic aberrations required and sufficient for transformation of normal T cells into lymphomas is unknown. Here, using a combinatorial in vitro-approach, we demonstrate that overexpression of MYC together with activated AKT in conditions of inhibition of intrinsic apoptosis rapidly resulted in transformation of mature mouse T cells with a frequency approaching 100%. Injection of transformed cells into mice resulted in rapid development of aggressive T cell lymphoma, characterized by spread to several organs, destruction of tissue architecture and rapid death of the animals. TcR-sequencing revealed a polyclonal repertoire of tumor cells indicating that co-expression of MYC, activated AKT and BCLXL is sufficient for tumor transformation and do not require acquisition of additional genetic events. When analyzing cells with inducible expression we found that proliferation of transformed T cells required sustained expression of both MYC and AKT. AKT exerted a dual function as it inhibited induction of, and promoted exit from, cellular quiescence and contributed to inhibion of apoptosis. Downregulation of AKT and/or MYC together with BCLXL resulted in rapid and complete elimination of cells through induction of apoptotic cell death.

THZ1 targeting CDK7 suppresses STAT transcriptional activity and sensitizes T-cell lymphomas to BCL2 inhibitors

Peripheral T-cell lymphomas (PTCL) are aggressive diseases with poor response to chemotherapy and dismal survival. Identification of effective strategies to target PTCL biology represents an urgent need. Here we report that PTCL are sensitive to transcription-targeting drugs, and, in particular, to THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7). The STAT-signalling pathway is highly vulnerable to THZ1 even in PTCL cells that carry the activating STAT3 mutation Y640F. In mutant cells, CDK7 inhibition decreases STAT3 chromatin binding and expression of highly transcribed target genes like MYC, PIM1, MCL1, CD30, IL2RA, CDC25A and IL4R. In surviving cells, THZ1 decreases the expression of STAT-regulated anti-apoptotic BH3 family members MCL1 and BCL-XL sensitizing PTCL cells to BH3 mimetic drugs. Accordingly, the combination of THZ1 and the BH3 mimetic obatoclax improves lymphoma growth control in a primary PTCL ex vivo culture and in two STAT3-mutant PTCL xenografts, delineating a potential targeted agent-based therapeutic option for these patients.

T-cell lymphomas are aggressive diseases associated with poor outcome. Here, the authors show that the THZ1, a CDK7 inhibitor, suppresses STAT transcriptional activity leading to apoptosis and sensitization to BCL2 inhibitors in T-cell lymphomas.

The histone deacetylase inhibitor romidepsin synergizes with lenalidomide and enhances tumor cell death in T-cell lymphoma cell lines

We investigated the cytotoxic interactions of romidepsin, a histone deacetylase inhibitor, and lenalidomide, an immunomodulatory agent, in a T-cell lymphoma preclinical model. Hut-78 and Karpas-299 cells were treated with romidepsin and lenalidomide alone and in combination. The interaction between romidepsin and lenalidomide was evaluated by the Chou-Talalay method, and cell viability and clonogenicity were also evaluated. Apoptosis, reactive oxygen species (ROS) levels, and cell cycle distribution were determined by flow cytometry. ER stress, caspase activation, and the AKT, MAPK/ERK, and STAT-3 pathways were analyzed by Western blot. Combination treatment with romidepsin and lenalidomide had a synergistic effect in Hut-78 cells and an additive effect in Karpas-299 cells at 24 hours and did not decrease the viability of normal peripheral blood mononuclear cells. This drug combination induced apoptosis, increased ROS production, and activated caspase-8, -9, -3 and PARP. Apoptosis was associated with increased hallmarks of ER stress and activation of UPR sensors and was mediated by dephosphorylation of the AKT, MAPK/ERK, and STAT3 pathways.The combination of romidepsin and lenalidomide shows promise as a possible treatment for T-cell lymphoma. This work provides a basis for further studies.

Survival control of malignant lymphocytes by anti-apoptotic MCL-1

Programmed apoptotic cell death is critical to maintain tissue homeostasis and cellular integrity in the lymphatic system. Accordingly, the evasion of apoptosis is a critical milestone for the transformation of lymphocytes on their way to becoming overt lymphomas. The anti-apoptotic BCL-2 family proteins are pivotal regulators of the mitochondrial apoptotic pathway and genetic aberrations in these genes are associated with lymphomagenesis and chemotherapeutic resistance. Pharmacological targeting of BCL-2 is highly effective in certain indolent B-cell lymphomas; however, recent evidence highlights a critical role for the BCL-2 family member MCL-1 in several lymphoma subtypes. MCL-1 is recurrently highly expressed in various kinds of cancer including non-Hodgkin's lymphoma of B- and T-cell origin. Moreover, both indolent and aggressive forms of lymphoma require MCL-1 for lymphomagenesis and for their continued survival. This review summarizes the role of MCL-1 in B- and T-cell lymphoma and discusses its potential as a therapeutic target.

Expression of Apoptosis-regulating Proteins Bcl-2 and Bax in Lymph Node Aspirates from Dogs with Lymphoma

Background

Dysregulated apoptosis is a hallmark of tumorigenesis, and is also involved in resistance to cytotoxic treatment, and might be relevant in lymphoma in dogs.

Hypothesis/Objectives

That Bcl‐2/Bax expression patterns differ between lymphoma immunophenotypes, and that Bcl‐2/Bax ratio is correlated with prognosis.

Animals

Fifty‐five client‐owned dogs with multicentric lymphoma and 5 healthy dogs.

Methods

Prospective, case–control study. We compared 3 methods (flow cytometry, qRT‐PCR, Western blot) for Bcl‐2 and Bax quantification in a subset of dogs. The effect of time on Bcl‐2/Bax ratios measured by flow cytometry was assessed in lymphoma cell lines. Immunophenotype and Bcl‐2/Bax expression by flow cytometry were determined in LN aspirates from all dogs with multicentric lymphoma compared to healthy dogs. Progression‐free survival (PFS) was retrospectively evaluated in a group of dogs all receiving similar treatment.

Results

Bcl‐2/Bax ratios remain consistent for at least 5 days after sample collection. Bcl‐2/Bax ratio was higher in dogs with T‐cell lymphoma (TCL; median 0.97, range 0.37–1.36) compared to B‐cell lymphoma (BCL; median 0.36, range 0.07–1.45) (P < .0001) and normal dogs (median 0.36, range 0.21–0.48) (P = .0006), respectively. Dogs with Bcl‐2/Bax ratios higher than the median of the group experienced a median PFS of 101 days and dogs with ratios equal and lower than the median had PFS of 130 days (P = .19).

Conclusions and clinical importance

Higher intrinsic resistance to apoptosis following cytotoxic treatment might contribute to the less favorable prognosis associated with multicentric TCL in dogs. Whether Bcl‐2/Bax will be helpful to identify canine BCL and TCL with more aggressive and more indolent behavior, respectively, should be evaluated in larger prospective clinical studies.

The role of aberrant proteolysis in lymphomagenesis

PURPOSE OF REVIEW

Deregulated proteolysis is increasingly being implicated in pathogenesis of lymphoma. In this review, we highlight the major cellular processes that are affected by deregulated proteolysis of critical substrates that promote lymphoproliferative disorders.

RECENT FINDINGS

Emerging evidence supports the role of aberrant proteolysis by the ubiquitin proteasome system (UPS) in lymphoproliferative disorders. Several UPS mediators are identified to be altered in lymphomagenesis. However, the precise role of their alteration and comprehensive knowledge of their target substrate critical for lymphomagenesis is far from complete.

SUMMARY

Many E3 ligase and deubiquitinases that contribute to regulated proteolysis of substrates critical for major cellular processes are altered in various lineages of lymphoma. Understanding of the proteolytic regulatory mechanisms of these major cellular pathways may offer novel biomarkers and targets for lymphoma therapy.

Crizotinib (PF-2341066) induces apoptosis due to downregulation of pSTAT3 and BCL-2 family proteins in NPM-ALK(+) anaplastic large cell lymphoma

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) is an aberrant fusion gene product with tyrosine kinase activity and is expressed in substantial subset of anaplastic large cell lymphomas (ALCL). It has been shown that NPM-ALK binds to and activates signal transducer and activator of transcription 3 (STAT3). Although NPM-ALK(+) ALCL overall shows a better prognosis, there is a sub-group of patients who relapses and is resistant to conventional chemotherapeutic regimens. NPM-ALK is a potential target for small molecule kinase inhibitors. Crizotinib (PF-2341066) is a small, orally bioavailable molecule that inhibits growth of tumors with ALK activity as shown in a subgroup of non-small lung cancer patients with EML4-ALK expression. In this study, we have investigated the in vitro effects of Crizotinib in ALCL cell line with NPM-ALK fusion. Crizotinib induced marked downregulation of STAT3 phosphorylation, which was associated with significant apoptotic cell death. Apoptosis induction was attributed to caspase-3 cleavage and marked downregulation of the Bcl-2 family of proteins including MCL-1. These findings implicate that Crizotinib has excellent potential to treat patients with NPM-ALK(+) ALCL through induction of apoptotic cell death and downregulation of major oncogenic proteins in this aggressive lymphoma.

Models for mature T-cell lymphomas--a critical appraisal of experimental systems and their contribution to current T-cell tumorigenic concepts

Mature T-cell lymphomas/leukemias (MTCL) have been understudied lymphoid neoplasms that currently receive growing attention. Our historically rudimentary molecular understanding and dissatisfactory interventional success in this complex and for the most part poor-prognostic group of tumors is only slightly improving. A major limiting aspect in further progress in these rare neoplasms is the lack of suitable model systems that would substantially facilitate pathogenic studies and pre-clinical drug evaluations. Such representations of MTCL have thus far not been systematically appraised. We therefore provide an overview on existing models and point out their particular advantages and limitations in the context of the specific scientific questions. After addressing issues of species-specific differences and classifications, we summarize data on MTCL cell lines of human as well as murine origin, on murine strain predispositions to MTCL, on available models of genetically engineered mice, and on transplant systems. From an in-silico meta-analysis of available primary data of gene expression profiles on human MTCL we cross-reference genes reported to transform T-cells in mice and reflect on their general vs entity-restricted relevance and on target-promoter influences. Overall, we identify the urgent need for new models of higher fidelity to human MTCL with respect to their increasingly recognized diversity and to predictions of drug response.

Expression of the Bcl-2 apoptotic marker in cats diagnosed with inflammatory bowel disease and gastrointestinal lymphoma

Immunolabeling for the critical lymphocyte survival factor, Bcl-2, of intestinal biopsies from cats with histologic evidence of inflammatory bowel disease (IBD) or gastrointestinal (GI) lymphoma was evaluated to determine if expression differed significantly between these two disease processes. Immunolabeling for Bcl-2 was performed on small intestinal endoscopic or full thickness biopsy sections from 55 cats. Diagnosis of IBD, T-cell lymphoma or B-cell lymphoma was established previously. The percentage of infiltrating lymphocytes that were positively labeled for Bcl-2 was subjectively determined for each case. Eight cats were diagnosed with IBD and 47 cats with lymphoma. A significantly higher percentage of cells were positively immunolabeled for Bcl-2 in cats with GI lymphoma [median (range); 90 (5-95)%] compared with cats with IBD [60 (15-95)%] (P = 0.029). However, the overall degree of positive immunolabeling in both groups tended to be high. This over-expression of Bcl-2 may prove useful as a therapeutic target for IBD and GI lymphoma in cats.

Clinical and laboratory characteristics of systemic anaplastic large cell lymphoma in Chinese patients

Background

Systemic anaplastic large cell lymphoma (S-ALCL) is a rare disease with a highly variable prognosis and no standard chemotherapy regimen. Anaplastic lymphoma kinase (ALK) has been reported as an important prognostic factor correlated with S-ALCL in many but not all studies. In our study, we retrospectively analyzed 92 patients with S-ALCL from the Peking University Lymphoma Center for clinical and molecular prognostic factors to make clear the role of ALK and other prognostic factors in Han Chinese S-ALCL.

Results

The majority of Chinese S-ALCL patients were young male patients (median age 26, male/female ratio 1.7) and the median age was younger than previous reports regardless of ALK expression status. The only statistically significant different clinical characteristic in S-ALCL between ALK positive (ALK⁺) and ALK negative (ALK^-) was age, with a younger median age of 22 for ALK⁺ compared with 30 for ALK^-. However, when pediatric patients (≤18) were excluded, there was no age difference between ALK⁺ and ALK^-. The groups did not differ in the proportion of males, those with clinical stage III/IV (49 vs 51%) or those with extranodal disease (53 vs 59%). Of 73 evaluable patients, the 3-year and 5-year survival rates were 60% and 47%, respectively. Univariate analysis showed that three factors: advanced stage III/IV, lack of expression of ALK, and high Ki-67 expression, were associated with treatment failure in patients with S-ALCL. However, ALK expression correlated with improved survival only in patients younger than 14 years, while not in adult patients. In multivariate analysis, only clinical stage was an independent prognostic factor for survival. Expressions of Wilms tumor 1 (WT1) and B-cell lymphoma 2 protein (BCL-2) correlated with the expression of ALK, but they did not have prognostic significance. High Ki-67 expression was also a poor prognostic factor.

Conclusions

Our results show that ALK expression alone is not sufficient to determine the outcome of ALCL and other prognostic factors must be considered. Clinical stage is an independent prognostic factor. Ki-67 expression is a promising prognostic factor.

Expression patterns of endothelin-1 and its receptors in colorectal cancer

BACKGROUND AND OBJECTIVES

Endothelin-1 (ET-1), a potent vasoconstricting peptide, plays an important role in carcinogenesis. Previous in vitro studies have shown that colorectal cancer cells produce ET-1.

METHODS

ET-1 and its receptors ET-A (ET(A) R) and ET-B (ET(B) R) were analyzed in colorectal cancer cell lines and tumors by Western blot and immunohistochemistry. Also, ET-1 levels were measured by ELISA in blood samples collected before and after tumor resection.

RESULTS

ET-1 was immunohistochemically expressed by tumor cells at a variable level in 39 cases tested. The adjacent normal mucosa was negative for ET-1 expression. Strong ET(A) R expression observed in the deeper infiltrating areas at the periphery of neoplastic tissue correlated significantly with tumor stage. ET(B) R levels were very low or undetectable. Western blot analysis in paired (normal, tumor) fresh-frozen samples of colorectal cancers and in four colon carcinoma cell lines confirmed these findings. In addition, lower levels of ET-1 in the peripheral circulation after the tumor resection were found by ELISA as compared to those observed before surgery.

CONCLUSIONS

ET-1 and ET(A) R, but not ET(B) R, are expressed at a higher level in primary and cultured colon carcinoma cells as compared to normal colon mucosa cells. Further functional studies are needed to explore the role of ET-1/ET(A) R axis in colon carcinogenesis.

New drug therapies in peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous collection of lymphomas that are associated with very poor prognosis. Conventional therapies, historically based on protocols for aggressive B-cell lymphomas, deliver less than adequate outcomes; the majority of patients experience early relapse after front-line treatment and current 5-year overall survival is only 10-30%. Clearly, new approaches are needed. In recent years there has been a plethora of novel agents showing activity in PTCL, often in patients with advanced relapsed or refractory disease. These agents include antifolate drugs (pralatrexate), histone deacetylase inhibitors (vorinostat, romidepsin, panobinostat and belinostat), nucleoside analogues (gemcitabine, forodesine and clofarabine), monoclonal antibodies (anti-CD52, anti-CD4 and anti-CD2), fusion toxins (denileukin diftitox), immunomodulatory agents (lenalidomide) and proteasome inhibitors (bortezomib). This is an exciting time in the treatment of PTCL, as our ever improving understanding of the distinguishing features, pathogenesis, molecular biology and progression of PTCL, and the knowledge of the mechanism and efficacy of novel therapies, may see a real improvement in outcomes for patients. The purpose of this article is to focus on these novel therapies and the results of recent clinical trials in PTCL.

Peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of clinically aggressive diseases associated with poor outcome. Studies that focus specifically on PTCL are emerging, with the ultimate goal of improved understanding of disease biology and the development of more effective therapies. However, one of the difficulties in classifying and studying treatment options in clinical trials is the rarity of these subtypes. Various groups have developed lymphoma classifications over the years, including the World Health Organization, which updated its classification in 2008. This article briefly reviews the major lymphoma classification schema, highlights contributions made by the collaborative International PTCL Project, discusses prognostic issues and gene expression profiling, and outlines therapeutic approaches to PTCL. These include the standard chemotherapeutic regimens and other modalities incorporating antifolates, conjugates, histone deacetylase inhibitors, monoclonal antibodies, nucleoside analogs, proteasome inhibitors, and signaling inhibitors. As this review emphasizes, the problem has now evolved into an abundance of drugs and too few patients available to test them. Collaborative groups will aid in future efforts to find the best treatment strategies to improve the outcome for patients with PTCL.

Molecular predictors of response in aggressive T-cell lymphomas

Aggressive T-cell lymphomas are a heterogeneous group of malignancies of mature T and natural killer cells, many of which have recently been identified as distinct entities in the classification of non-Hodgkin lymphomas according to the World Health Organization. Owing in part to a limited understanding of the molecular features and pathogenesis of many of these disorders, treatment strategies using conventional lymphoma regimens have been used, with generally inferior outcomes. Recent data are now emerging from gene expression profiling and molecular analysis of tumors, which has led to development of novel, targeted therapeutic strategies and has provided a basis for more accurate diagnosis and prognostic characterization.

Expression of serine 194-phosphorylated Fas-associated death domain protein correlates with proliferation in B-cell non-Hodgkin lymphomas

Fas-associated death domain protein is a key component of the extrinsic apoptotic pathway. In addition, in animal models, Fas-associated death domain protein phosphorylation at serine 194 has been shown to affect cell proliferation, especially in T lymphocytes. The importance of Fas-associated death domain protein phosphorylation at serine 194 for the proliferation of B lymphocytes, however, is uncertain. Here we show in reactive lymph nodes that serine 194 phosphorylated Fas-associated death domain protein is expressed predominantly in the dark (proliferative) zone of germinal centers. In B-cell non-Hodgkin lymphoma cell lines, serine 194 phosphorylated Fas-associated death domain protein levels are substantially higher in highly proliferating cells and lower in serum-starved cells. We also used immunohistochemical analysis to assess Fas-associated death domain protein phosphorylation at serine 194 expression in 122 B-cell non-Hodgkin-type lymphomas. The mean percentage of serine 194 phosphorylated Fas-associated death domain protein positive tumor cells was 81% in Burkitt lymphoma, 41% in diffuse large B-cell lymphoma, 18% in follicular lymphoma, 18% in plasma cell myeloma, 12% in extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue, 11% in mantle cell lymphoma, and 2% in chronic lymphocytic leukemia/small lymphocytic lymphoma (P < .0001, Kruskal-Wallis test). Furthermore, in chronic lymphocytic leukemia/small lymphocytic lymphoma, serine 194 phosphorylated Fas-associated death domain protein was detected predominantly in proliferation centers. In the entire study group, the percentage of cells positive for serine 194 phosphorylated Fas-associated death domain protein correlated significantly with the proliferation index Ki-67 (Spearman R = 0.9, P < .0001). These data provide evidence that serine 194 phosphorylated Fas-associated death domain protein is involved in the proliferation of normal and neoplastic B cells and has features of a novel proliferation marker.

Spectrum of CD30+ lymphoid proliferations in the eyelid lymphomatoid papulosis, cutaneous anaplastic large cell lymphoma, and anaplastic large cell lymphoma

PURPOSE

To report the clinicopathologic features of 3 patients with CD30(+) lymphoid proliferations of the eyelid.

DESIGN

Retrospective case series.

PARTICIPANTS

Patients with cutaneous CD30(+) lymphoproliferative lesions of the eyelid.

METHODS

Three patients with CD30(+) non-mycosis fungoides T-cell lymphoid infiltrates of the eyelid were identified. The histories, clinical findings, pathologic features including immunohistochemical staining, treatments, and outcomes were reviewed and compared.

MAIN OUTCOME MEASURES

Pathologic findings including immunohistochemical analysis.

RESULTS

The patients included an 81-year-old man, an 18-year-old man, and a 42-year-old woman with CD30(+) lymphoid proliferations of the eyelid and adjacent soft tissue. The first patient had an isolated crateriform eyelid lesion that was classified as lymphomatoid papulosis (LyP). The second patient had an isolated multinodular lesion of the eyelid that was classified as cutaneous anaplastic large cell lymphoma (cALCL). The third patient presented with eyelid edema with an underlying mass and was found to have widely disseminated anaplastic large cell lymphoma (ALCL). Diagnoses were dependent on clinical findings.

CONCLUSIONS

The CD30(+) lymphoid proliferations represent a spectrum of conditions ranging from indolent LyP, to moderately aggressive cALCL, to highly aggressive ALCL. Interpretation of the pathologic findings in CD30(+) lymphoid proliferations is based in part on clinical findings.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any material discussed in this article.

The therapeutic potential of p53 reactivation by nutlin-3a in ALK+ anaplastic large cell lymphoma with wild-type or mutated p53

p53 is expressed frequently, but is rarely mutated in anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) tumours. Nutlin-3a is a recently developed small molecule that targets Mdm2, a critical negative regulator of p53, and disrupts the p53-Mdm2 interaction resulting in p53 stabilization and activation. We show that nutlin-3a activates p53 in ALK+ ALCL cells carrying a wild type (wt) or mutated but partially functional p53 gene resulting in p53-dependent cell-cycle arrest and apoptosis. Cell-cycle arrest was associated with upregulation of the cyclin-dependent kinase inhibitor p21. Nutlin-3a-induced apoptotic cell death was accompanied by Bax and Puma upregulation, downregulation of Bcl-xl, survivin, and caspase-3 cleavage, and this was reduced when p53-dependent transactivation activity was inhibited by pifithrin-alpha, or when pifithrin-mu was used to inhibit direct p53 targeting of mitochondria. Nutlin-3a sensitized the activation of the extrinsic apoptotic pathway in wt-p53 ALK+ ALCL cells, in part, through upregulation of DR-5 and downregulation of c-Flip(S/L), and was synergistic with TRAIL in cell death induction. In addition, nutlin-3a treatment enhanced doxorubicin cytotoxicity against ALK+ ALCL cells harbouring mt p53, and this was associated with p73 upregulation. These data suggest that disruption of the p53-mdm2 interaction by nutlin-3a offers a novel therapeutic approach for ALK+ ALCL patients.

Mitochondrial gateways to cancer

Mitochondria are required for cellular survival, yet can also orchestrate cell death. The peculiar biochemical properties of these organelles, which are intimately linked to their compartmentalized ultrastructure, provide an optimal microenvironment for multiple biosynthetic and bioenergetic pathways. Most intracellular ATP is generated by mitochondrial respiration, which also represents the most relevant source of intracellular reactive oxygen species. Mitochondria participate in a plethora of anabolic pathways, including cholesterol, cardiolipin, heme and nucleotide biosynthesis. Moreover, mitochondria integrate numerous pro-survival and pro-death signals, thereby exerting a decisive control over several biochemical cascades leading to cell death, in particular the intrinsic pathway of apoptosis. Therefore, it is not surprising that cancer cells often manifest the deregulation of one or several mitochondrial functions. The six classical hallmarks of cancer (i.e., limitless replication, self-provision of proliferative stimuli, insensitivity to antiproliferative signals, disabled apoptosis, sustained angiogenesis, invasiveness/metastatic potential), as well as other common features of tumors (i.e., avoidance of the immune response, enhanced anabolic metabolism, disabled autophagy) may directly or indirectly implicate deregulated mitochondria. In this review, we discuss several mechanisms by which mitochondria can contribute to malignant transformation and tumor progression.

Gene Expression Profiling in Anaplastic Large Cell Lymphoma and Hodgkin's Disease

Recent efforts have been made to isolate molecular targets that could explain different outcome between histological subtypes of lymphomas and to understand the molecular mechanisms underlying oncogenic events. Using the SSH technique, we compared the transcriptome of 2 cases of ALK+ and ALK- anaplastic large cell lymphoma (ALCL) and of 2 cases of classical Hodgkin's lymphoma (cHL) with opposite behavior. Regarding ALCL, we showed that ALK-positive tumors overexpressed genes involved in different signaling pathways such as activation or signaling of T-cells, regulation of apoptosis, phospholipase Cgamma and phosphatidyl inositol-3 Kinase. In addition, the characterization of a specific molecular signature may be of clinical relevance since ALK+ tumors generally have a better prognosis than ALK- ones. Similar problems of differential prognosis is observed in cases of cHL, which in addition, may be morphologically and immunologically indistinguishable. Therefore, we applied the same SSH technique to 2 cHL samples from patients with favorable and poor outcome, respectively. Forty-four cDNAs were significantly overexpressed in the poor outcome case. In addition to the defender against death cell 1 (DAD1) gene, overexpressed clones corresponded mostly to expressed sequence tags (ESTs). Interestingly, the present study identifies new genes which may be involved in the pathogenesis and/or clinical outcome of cHL and deserve further investigations.

Need for an improved molecular/genetic classification for CD30+ lymphomas involving the skin

BACKGROUND

The spectrum of diseases that constitute the CD30+ lymphomas, with lymphomatoid papulosis (LyP) at one end, and anaplastic large-cell lymphoma (ALCL) at the other end, shows variable morphology, immunophenotype, and clinical behavior. The border between these diseases is sometimes difficult to establish and there are many grey zones in their classification.

METHODS

We reviewed the clinical and research literature and guided by our experiences attempted to discern molecular and phenotypic criteria to improve the classification and identify molecular targets for therapy of CD30-positive cutaneous lymphomas.

RESULTS

Functional studies of ALCL cell lines clonally derived from LyP have revealed loss of growth inhibition by transforming growth factor beta (TGF-beta), due to TGF-beta receptor mutations. Studies of genetic variants of the CD30 promoter showed distinct microsatellite alleles associated with development of LyP and lymphoma progression. Studies of LyP and cutaneous ALCL tissues and cell lines suggest a dual role for CD30/CD30 ligand interactions in regression of LyP and progression to lymphoma. CD30 signaling activates NF-kappaB in cell lines derived from cutaneous ALCL but not anaplastic lymphoma kinase (ALK)-positive systemic ALCL in which growth arrest occurs through cell cycle inhibitor p21WAF1/Cip1. Other likely biomarkers of disease progression include differential expression of Bcl-2, fascin, cutaneous lymphocyte antigen, and T-cell receptor clonality. These may lead to improved classification, diagnoses, and therapeutic targets.

CONCLUSIONS

The current clinicopathologic classification of CD30+ cutaneous lymphoproliferative disorders is insufficient. Incorporating genetic and molecular criteria would better define the borders between benign/ malignant and aggressive/nonaggressive disorders.

Interleukin-10 gene polymorphism influences the prognosis of T-cell non-Hodgkin lymphomas

Interleukin-10 (IL-10) is one of the cytokines implicated in the pathogenesis of diffuse large B-cell lymphoma (DLBCL) in which it acts as auto/paracrine growth factor for lymphoma growth. T-cell non-Hodgkin lymphoma (NHL) is a heterogeneous disease, the biological basis of which is not fully understood. Some evidence suggests that IL-10 might be associated with the progression of T-cell NHLs and that IL-10 may be involved in a rescue effect, protecting T cells from apoptotic cell death associated with upregulated bcl-2 expression. The current study evaluated the impact of IL-10 gene (IL10) polymorphism on the response to chemotherapy and survival in T-cell NHL. IL10 polymorphisms were determined in 108 patients with T-cell NHL. The response to chemotherapy was not dependent on IL10 polymorphism, while survival differed significantly according to IL10 polymorphism. The group with ATA haplotype showed superior overall survival (61.2 +/- 5.9% vs. 21.2 +/- 11.7%, P = 0.001) and failure-free survival (35.0 +/- 5.7% vs. 13.2 +/- 8.7%, P = 0.001) compared to those without ATA haplotype. The ATA haplotype was identified as a favourable prognostic factor compared to non-ATA haplotype (P = 0.037, hazard ratio 2.1), together with international prognostic index (IPI) in a multivariate model for overall survival. In conclusion, IL10 polymorphism may affect the survival of T-cell NHL patients.

Differential expression of the human MIXL1 gene product in non-Hodgkin and Hodgkin lymphomas

The Mix1 homeobox-like (MIXL1) gene encodes a paired class homeobox transcription factor that is involved in embryogenesis. Previous studies have shown that the MIXL1 gene product is expressed in B- and T-cell progenitors of normal bone marrow and, in some cell lines derived from hematopoietic neoplasms. The status of MIXL1 expression and subcellular localization in human lymphomas is unknown. Using a highly specific antibody, we assessed for MIXL1 expression in lymphoma cell lines of B- and T-cell lineage by reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemistry. We also assessed for MIXL1 expression using immunohistochemical methods in 193 lymphoid tumors, including 140 B-cell non-Hodgkin lymphomas (NHL), 36 T-cell NHL, and 17 Hodgkin lymphomas (HL). MIXL1 was detected predominantly in the nuclear fraction of all cell lines tested and was predominantly nuclear in primary tumor specimens. Based on the distribution of the staining results (histogram), a 50% cutoff was selected for high versus low MIXL1 expression. High MIXL1 expression was detected more frequently in Burkitt lymphoma and diffuse large B-cell lymphoma compared with other types of B-cell NHL (P < .0001, chi(2) test). Most cases of T-cell NHL and all cases of HL also highly expressed MIXL1. Most plasma cell myelomas were negative for MIXL1, but rare cases had low MIXL1 expression. MIXL1 expression significantly correlated with proliferation index (Ki-67) in B-cell NHL (P < .0001). The frequent and high expression of MIXL1 in aggressive B-cell NHL, T-cell NHL, and HL suggests that MIXL1 may be involved in lymphomagenesis.

Larger than life: Mitochondria and the Bcl-2 family

The intrinsic pathway of apoptosis relies on mitochondrial membrane permeabilization, with Bcl-2 proteins serving as its master regulators. They form a complex network of interactions both within the family and with multiple cellular factors outside the family. The understanding of the processes that regulate mitochondrial breach, and mechanisms that direct the pro- and anti-apoptotic functions of Bcl-2 proteins, should assist the development of novel anticancer therapies. Thus, it is of no surprise that research in the field is gaining momentum. In this review we outline the current concepts on regulatory circuits governing mitochondrial rupture and action of Bcl-2 proteins during cell death, and how this burgeoning knowledge is being translated into the clinics with the hope to combat cancer.

Complex secondary chromosome abnormalities in advanced stage anaplastic large cell lymphoma of children and adolescents: a report from CCG-E08

Among pediatric non-Hodgkin lymphomas, one of the most distinctive types is anaplastic large cell lymphoma (ALCL). Specific chromosomal abnormalities are associated with prognosis in childhood acute lymphoblastic leukemia, but chromosome abnormalities have not been evaluated for prognostic value in pediatric ALCL. For Children's Cancer Group protocol CCG-E-08 Etiologic Study of Non-Hodgkin Lymphoma in Childhood, three patients were enrolled with cytogenetic analysis of ALCL and simultaneously enrolled on treatment protocol CCG-552. Pathology material and karyotypes at initial diagnosis underwent central review. Demographics included ages of 9, 12, and 14 years, and a male/female ratio of 1:2. All patients had advanced disease (stage III). Disease progressed or relapsed in two patients, and one died. Chromosomal abnormalities, including t(2;5)(p23;q35), the ALK/NPM fusion gene, and complex karyotypes with multiple additional abnormalities, were identified in all three patients. In two patients with progressive disease or relapse, additional chromosomal abnormalities at 1q21 and 10q24, possibly involving MCL1 and HOX11/TCL3, respectively, may have contributed to worse outcome. Pediatric ALCL cases frequently have complex karyotypes and usually involve ALK/NPM translocations in this limited study. Additional chromosome abnormalities may be involved in the pathogenesis of ALCL. Further studies are warranted in larger cohorts of children and adolescents with ALCL.

Lymphomas involving the pleura: a clinicopathologic study of 34 cases diagnosed by pleural biopsy

CONTEXT

Pleural involvement by lymphoma is relatively common. However, there are very few clinicopathologic studies reported in the literature of lymphomas involving the pleura.

OBJECTIVE

To characterize the clinicopathologic features of lymphomas involving the pleura.

DESIGN

We reviewed the clinicopathologic features of 34 patients with lymphoma involving the pleura proven by biopsy and classified these neoplasms using the World Health Organization classification.

RESULTS

There were 22 men and 12 women, with an average age of 62 years (range, 22-82 years). Nine (26.5%) patients had pleural involvement as the only site of disease, 22 (64.7%) had other sites of involvement, and 3 (8.8%) had inadequate staging data. Eighteen (56.2%) of 32 patients with adequate clinical data had a history of lymphoma (including 3 patients with pleural involvement as the only disease site). In 29 (85.3%) cases, a specific diagnosis according to the World Health Organization classification could be made: 17 (58.6%) diffuse large B-cell lymphoma, 5 (17.2%) follicular lymphoma (including a case with areas of diffuse large B-cell lymphoma), 2 (6.9%) small lymphocytic lymphomas/chronic lymphocytic leukemia, 2 (6.9%) precursor T-cell lymphoblastic lymphoma/leukemia, 1 (3.4%) mantle cell lymphoma, 1 (3.4%) posttransplant lymphoproliferative disorder, and 1 (3.4%) classical Hodgkin lymphoma. The other 5 cases were B-cell lymphomas that could not be further classified. Cytologic examination of pleural fluid was performed in 15 cases and was positive for lymphoma in 8 (53.3%) cases.

CONCLUSIONS

Most patients with lymphoma involving the pleura have simultaneous evidence of systemic involvement. The most frequent type is diffuse large B-cell lymphoma, followed by follicular lymphoma. Cytologic examination can have negative results in patients with pleural involvement by lymphoma.

Clinical role of Bcl-2, Bax, or p53 overexpression in peripheral T-cell lymphomas

Apoptosis pathways are known to be involved in the pathogenesis of peripheral T-cell lymphomas (PTCLs). As such, the current study attempted to investigate the overexpression of Bcl-2, Bax, or p53 with respect to the progression of PTCL. Paraffin-embedded specimens from 74 patients were analyzed immunohistochemically for Bcl-2, Bax, or p53 overexpression including PTCL-unspecified (n=45), extranodal natural killer cell/T-cell lymphoma (n=10), angioimmunoblastic T-cell lymphoma (n=7), anaplastic large cell lymphoma (n=7), and cutaneous T-cell lymphoma (n=5). The Bcl-2 overexpression was exhibited in 33 (45%), Bax, 17 (23%), and p53, 33 patients (45%). Bcl-2 overexpression was strongly associated with advanced stage (p=0.021) and higher international prognostic indices (IPI) (p=0.038). Bcl-2(+)/p53(+) group was found to be associated with advanced stage (p=0.008) and higher IPI (p=0.001), compared with the other groups. The independent expression of Bcl-2 or p53 was not correlated with survival. Meanwhile, when confined to Bcl-2 overexpressing groups, p53 overexpression was significantly associated with poor survival (p=0.05), as the 3-year OS rate was 82.5% for Bcl-2(+)/p53- cases, yet only 32.9% for Bcl-2(+)/p53(+) cases. Multivariate analyses for OS found the Bcl-2/p53 co-expression (p=0.004) as independent prognostic factor, together with advanced stage (p<0.001) and higher prognostic index for PTCL (p=0.008). Bcl-2 overexpression seemed to correlate with the progression of PTCL interacting with a p53-dependent pathway.

The Role of Alemtuzumab in the Management of T-Cell Malignancies

T-cell malignancies are rare, making up 10% to 15% of all lymphoid neoplasms in adults. They include many different types of disorders such as T-cell prolymphocytic leukemia, T-cell large granular lymphocytic leukemia, adult T-cell leukemia/lymphoma, cutaneous T-cell lymphoma, and peripheral T-cell lymphoma, which are themselves divided into multiple subcategories. Most T-cell malignancies arise as a result of chromosomal abnormalities, including T-cell receptor rearrangement anomalies. Viral infections are implicated in the development of adult T-cell leukemia/lymphoma and some cases of peripheral T-cell lymphoma have been linked to Epstein-Barr virus or human immunodeficiency virus infection. With the possible exception of T-cell large granular lymphocytic leukemia, which often has an indolent course, T-cell malignancies have not responded well to conventional chemotherapeutic treatment. The introduction of monoclonal antibodies for the treatment of cancer has changed the outlook for patients with T-cell malignancies. Recent studies with single-agent alemtuzumab, an anti-CD52 monoclonal antibody, have shown improved response rates and survival in patients with T-cell prolymphocytic leukemia and cutaneous T-cell lymphoma. Preliminary data also suggest that alemtuzumab may have activity in patients with heavily pretreated peripheral T-cell lymphoma who are refractory to conventional chemotherapy. Preclinical studies with mice bearing human adult T-cell leukemia/lymphoma cells suggest that alemtuzumab may have a potential therapeutic role in this setting. Treatment of T-cell hematologic malignancies with alemtuzumab appears promising. Earlier treatment and combination with chemotherapeutic agents may improve treatment outcome for patients with these malignancies and allow for consolidation with stem cell transplant strategies in selected patients.

Gene expression profiling identifies molecular subgroups among nodal peripheral T-cell lymphomas

The classification of peripheral T-cell lymphomas (PTCL) is still a matter of debate. To establish a molecular classification of PTCL, we analysed 59 primary nodal T-cell lymphomas using cDNA microarrays, including 56 PTCL and three T-lymphoblastic lymphoma (T-LBL). The expression profiles could discriminate angioimmunoblastic lymphoma, anaplastic large-cell lymphoma and T-LBL. In contrast, cases belonging to the broad category of 'PTCL, unspecified' (PTCL-U) did not share a single molecular profile. Using a multiclass predictor, we could separate PTCL-U into three molecular subgroups called U1, U2 and U3. The U1 gene expression signature included genes known to be associated with poor outcome in other tumors, such as CCND2. The U2 subgroup was associated with overexpression of genes involved in T-cell activation and apoptosis, including NFKB1 and BCL-2. The U3 subgroup was mainly defined by overexpression of genes involved in the IFN/JAK/STAT pathway. It comprised a majority of histiocyte-rich PTCL samples. Gene Ontology annotations revealed different functional profile for each subgroup. These results suggest the existence of distinct subtypes of PTCL-U with specific molecular profiles, and thus provide a basis to improve their classification and to develop new therapeutic targets.