Non-Hodgkin's lymphoma: review of conventional treatments

High monocytic MDSC signature predicts multi-drug resistance and cancer relapse in non-Hodgkin lymphoma patients treated with R-CHOP

Introduction

Non-Hodgkin Lymphoma (NHL) is a heterogeneous lymphoproliferative malignancy with B cell origin. Combinatorial treatment of rituximab, cyclophsphamide, hydroxydaunorubicin, oncovin, prednisone (R-CHOP) is the standard treatment regimen for NHL, yielding a complete remission (CR) rate of 40-50%. Unfortunately, considerable patients undergo relapse after CR or initial treatment, resulting in poor clinical implications. Patient's response to chemotherapy varies widely from static disease to cancer recurrence and later is primarily associated with the development of multi-drug resistance (MDR). The immunosuppressive cells within the tumor microenvironment (TME) have become a crucial target for improving the therapy efficacy. However, a better understanding of their involvement is needed for distinctive response of NHL patients after receiving chemotherapy to design more effective front-line treatment algorithms based on reliable predictive biomarkers.

Methods

Peripheral blood from 61 CD20+ NHL patients before and after chemotherapy was utilized for immunophenotyping by flow-cytometry at different phases of treatment. In-vivo and in-vitro doxorubicin (Dox) resistance models were developed with murine Dalton's lymphoma and Jurkat/Raji cell-lines respectively and impact of responsible immune cells on generation of drug resistance was studied by RT-PCR, flow-cytometry and colorimetric assays. Gene silencing, ChIP and western blot were performed to explore the involved signaling pathways.

Results

We observed a strong positive correlation between elevated level of CD33+CD11b+CD14+CD15- monocytic MDSCs (M-MDSC) and MDR in NHL relapse cohorts. We executed the role of M-MDSCs in fostering drug resistance phenomenon in doxorubicin-resistant cancer cells in both in-vitro, in-vivo models. Moreover, in-vitro supplementation of MDSCs in murine and human lymphoma culture augments early expression of MDR phenotypes than culture without MDSCs, correlated well with in-vitro drug efflux and tumor progression. We found that MDSC secreted cytokines IL-6, IL-10, IL-1β are the dominant factors elevating MDR expression in cancer cells, neutralization of MDSC secreted IL-6, IL-10, IL-1β reversed the MDR trait. Moreover, we identified MDSC secreted IL-6/IL-10/IL-1β induced STAT1/STAT3/NF-κβ signaling axis as a targeted cascade to promote early drug resistance in cancer cells.

Conclusion

Our data suggests that screening patients for high titre of M-MDSCs might be considered as a new potential biomarker and treatment modality in overcoming chemo-resistance in NHL patients.

Impact of transitioning inpatient chemotherapy regimens to the outpatient setting

BACKGROUND

Chemotherapy regimens historically have required admission of the patient to the hospital for extended infusions running over multiple days to complete each cycle of therapy. With the evolution of monitoring strategies readily available, a renaissance in patient care and healthcare cost utilization is necessary as transitioning the administration of these agents to the outpatient setting is seemingly achievable and is potentially more cost-effective.

PURPOSE

This evaluation sought to primarily measure cost-savings for an institution by transitioning inpatient chemotherapy regimens to the outpatient setting. Secondary outcomes evaluated the effect of this transition on overall patient length of stay, prevalence of adverse effects, and overall chemotherapy schedule adherence as a result of implementing transitions in sites of care. Barriers to receiving care in the outpatient setting were assessed by evaluating the acuity of performance status as well as distance from the hospital.

METHODS

This single-center retrospective, quantitative chart and expense analysis evaluated patients receiving rituximab, etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin (R-EPOCH) or rituximab, ifosfamide, carboplatin, and etoposide (R-ICE) chemotherapy regimens based on treatment setting at a single institution. Included patients were treated at the University of Chicago Medical Center. Those receiving inpatient-only management as compared with patients who received therapy in outpatient settings were compared in a matched cohort analysis. The control group was matched from the period before transition of therapy was instituted between November 2014 and November 2015, with those patients transitioned to outpatient therapy (December 2015 to November 2016), using demographic, diagnostic, treatment, and clinical status data to assure group similarity. Mean cost of therapy was compared between inpatient and outpatient regimens. Descriptive and demographic categorical data were compared using the Fisher's exact test. Continuous data were evaluated using the Student's t test. A significance level of alpha <0.05 was used for all analysis.

RESULTS

The cost of R-EPOCH therapy represented a significant difference across groups. R-ICE therapy similarly saw significant cost differences between inpatient and outpatient groups. If this was made standard of care for qualifying patients a retrospective annualized estimation of $466,507.85 with R-EPOCH therapy and $205,977.60 for R-ICE therapy could have been saved if this was utilized for patients who previously received their therapy as an inpatient.

CONCLUSION

The population of patients cared for at the University of Chicago Medicine during this time-period qualified for outpatient treatment for those treated with R-EPOCH and R-ICE regimens with no significantly identifiable prohibitive barriers between groups. As no significant complications manifested, it is reasonable to continue transitioning patients receiving these regimens to the outpatient setting where appropriate. R-EPOCH and R-ICE therapies were shown to be reasonable outpatient therapy while providing significant cost-savings for the institution.

Lymphoma Immunotherapy: Current Status

The rationale to treat lymphomas with immunotherapy comes from long-standing evidence on their distinctive immune responsiveness. Indolent B-cell non-Hodgkin lymphomas, in particular, establish key interactions with the immune microenvironment to ensure prosurvival signals and prevent antitumor immune activation. However, reports of spontaneous regressions indicate that, under certain circumstances, patients develop therapeutic antitumor immunity. Several immunotherapeutic approaches have been thus developed to boost these effects in all patients. To date, targeting CD20 on malignant B cells with the antibody rituximab has been the most clinically effective strategy. However, relapse and resistance prevent to cure approximately half of B-NHL patients, underscoring the need of more effective therapies. The recognition of B-cell receptor variable regions as B-NHL unique antigens promoted the development of specific vaccines to immunize patients against their own tumor. Despite initial promising results, this strategy has not yet demonstrated a sufficient clinical benefit to reach the regulatory approval. Several novel agents are now available to stimulate immune effector functions or counteract immunosuppressive mechanisms, such as engineered antitumor T cells, co-stimulatory receptor agonist, and immune checkpoint-blocking antibodies. Thus, multiple elements can now be exploited in more effective combinations to break the barriers for the induction of anti-lymphoma immunity.

[The establishment of Raji drug-resistant cell line and analyses of prohibitin and miR-27a expression]

OBJECTIVE

To establish Raji adriamycin (ADR)-resistant cell lines and analysis the expression of mitochondria Prohibitin (PHB) and microRNA-27a (miR-27a), as well as discuss its clinical significance.

METHODS

Built ADR-resistant Raji cells, detected their resistant index and drug-resistant spectrum and stability, observed their morphology and growth characteristics in general; evaluated the expression of phb mRNA and miR-27a in ADR-resistant cells (Raji/A) and sensitive cells (Raji/S) via real-time quantitative polymerase chain reaction (RT-PCR).

RESULTS

The ADR-resistant Raji cell lines were built; expression of PHB1 mRNA in Raji/A was evidently higher than in Raji/S (P<0.05), the expressing difference of PHB2 mRNA in Raji/A and Raji/S was statistically meaningless (P>0.05), the expression of miR-27a in Raji/A was much higher than in Raji/S (P<0.05).

CONCLUSION

By building the experimental model of Raji ADR-resistant cell lines, high expression level of PHB1 and miR-27a were detected in the cell lines, indicating that PHB1 and miR-27a may be associated with ADR-resistance of Raji cells.

Non-Hodgkin's B-cell lymphoma: advances in molecular strategies targeting drug resistance

Non-Hodgkin's lymphoma (NHL) is a heterogeneous class of cancers displaying a diverse range of biological phenotypes, clinical behaviours and prognoses. Standard treatments for B-cell NHL are anthracycline-based combinatorial chemotherapy regimens composed of cyclophosphamide, doxorubicin, vincristine and prednisolone. Even though complete response rates of 40-50% with chemotherapy can be attained, a substantial proportion of patients relapse, resulting in 3-year overall survival rates of about 30%. Relapsed lymphomas are refractory to subsequent treatments with the initial chemotherapy regimen and can exhibit cross-resistance to a wide variety of anticancer drugs. The emergence of acquired chemoresistance thus poses a challenge in the clinic preventing the successful treatment and cure of disseminated B-cell lymphomas. Gene-expression analyses have increased our understanding of the molecular basis of chemotherapy resistance and identified rational targets for drug interventions to prevent and treat relapsed/refractory diffuse large B-cell lymphoma. Acquisition of drug resistance in lymphoma is in part driven by the inherent genetic heterogeneity and instability of the tumour cells. Due to the genetic heterogeneity of B-cell NHL, many different pathways leading to drug resistance have been identified. Successful treatment of chemoresistant NHL will thus require the rational design of combinatorial drugs targeting multiple pathways specific to different subtypes of B-cell NHL as well as the development of personalized approaches to address patient-to-patient genetic heterogeneity. This review highlights the new insights into the molecular basis of chemorefractory B-cell NHL that are facilitating the rational design of novel strategies to overcome drug resistance.

Pharmacokinetics and tolerability of human mouse chimeric anti-CD22 monoclonal antibody in Chinese patients with CD22-positive non-Hodgkin lymphoma

The safety and pharmacokinetics assessment of antibodies targeting CD22 (e.g., epratuzumab) have been established in western Caucasian populations, but there are no reports of the effects in Chinese populations. This dose-escalation study examines the safety, pharmacokinetics and biologic effects of multiple doses of anti-CD22 human-murine chimeric monoclonal antibody SM03 in 21 Chinese patients with CD22-positive non-Hodgkin lymphoma. Most of drug-related adverse events (AEs) were mild and reversible. Two patients experienced serious AEs (hemorrhage); one patient had grade 4 neutropenia; one patient had asymptomatic grade III prolongation of activated partial thromboplastin time (APTT). Major AEs included fever (71%), prolongation of APTT (42.8%), leukocytopenia (44.4%), alanine transaminase elevation (28.6%), elevated serum creatinine (23.8%) and injection site skin redness (14.3%). Circulating B cells transiently decreased without significant effects on T cells or immunoglobulin levels. Pharmacokinetic data revealed that mean maximum observed SM03 concentration and mean AUC from time zero to infinity increased in a dose-dependent manner up to 360 mg/m (2) SM03. Mean clearance was similar at doses ≤ 360 mg/m (2) and decreased significantly at dose 480 mg/m (2), supporting saturation of B-cell binding at 360 mg/m (2). Across all dose levels and histologies, one patient achieved partial response at 480 mg/m (2) dose; 14 patients had stable disease as best response and four patients progressed. Overall, SM03 was tolerated at doses ranging from 60-480 mg/m (2) and had potential efficacy in Chinese patients with follicular lymphoma.

Global effects of adriamycin treatment on mouse splenic protein levels

Adriamycin (ADR) is a potent anticancer drug used to treat a variety of cancers. Patients treated with ADR have experienced side effects such as heart failure, cardiomyopathy, and "chemobrain", which have been correlated to changes in protein expression in the heart and brain. In order to better understand cellular responses that are disrupted following ADR treatment in immune tissues, this work focuses on spleen. Significantly reduced spleen sizes were found in ADR-treated mice. Global isotopic labeling of tryptic peptides and nanoflow reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) were employed to determine differences in the relative abundances of proteins from ADR-treated mice relative to controls. Fifty-nine proteins of the 388 unique proteins identified showed statistically significant differences in expression levels following acute ADR treatment. Differentially expressed proteins are involved in processes such as cytoskeletal structural integrity, cellular signaling and transport, transcription and translation, immune response, and Ca(2+) binding. These are the first studies to provide insight to the downstream effects of ADR treatment in a peripheral immune organ such as spleen using proteomics.

Serological identification of HSP105 as a novel non-Hodgkin lymphoma therapeutic target

We reported that the clinical efficacy of dendritic cell–based vaccination is strongly associated with immunologic responses in relapsed B-cell non-Hodgkin lymphoma (B-NHL) patients. We have now investigated whether postvaccination antibodies from responders recognize novel shared NHL-restricted antigens. Immunohistochemistry and flow cytometry showed that they cross-react with allogeneic B-NHLs at significantly higher levels than their matched prevaccination samples or nonresponders' antibodies. Western blot analysis of DOHH-2 lymphoma proteome revealed a sharp band migrating at approximately 100 to 110 kDa only with postvaccine repertoires from responders. Mass spectrometry identified heat shock protein-105 (HSP105) in that molecular weight interval. Flow cytometry and immunohistochemistry disclosed HSP105 on the cell membrane and in the cytoplasm of B-NHL cell lines and 97 diagnostic specimens. A direct correlation between HSP105 expression and lymphoma aggressiveness was also apparent. Treatment of aggressive human B-NHL cell lines with an anti-HSP105 antibody had no direct effects on cell cycle or apoptosis but significantly reduced the tumor burden in xenotransplanted immunodeficient mice. In vivo antilymphoma activity of HSP105 engagement was associated with a significant local increase of Granzyme B+ killer cells that very likely contributed to the tumor-restricted necrosis. Our study adds HSP105 to the list of nononcogenes that can be exploited as antilymphoma targets.

Comparative mitochondrial proteomic analysis of Rji cells exposed to adriamycin

The antitumor mechanisms of adriamycin (ADR) have been thought to contribute to induction of apoptosis and inefficiency of DNA repair, processes that are to a large extent mediated by mitochondria. This study aimed to investigate characteristics of ADR, including its antineoplastic activity, drug resistance, and unexpected toxicity in non-Hodgkin lymphoma (NHL) Raji cells at the mitochondrial proteomic level. The alterations of the mitochondrial proteome of Raji cells treated with ADR were analyzed by two-dimensional differential in-gel electrophoresis (2D-DIGE) coupled with linear ion trap quadrupole-electrospray ionization tandem mass spectrometry (LTQ-ESI-MS/MS).The altered patterns of three identified proteins were validated by Western blot and analyzed by pathway studio software. The results showed that 34 proteins were downregulated and 3 proteins upregulated in the study group compared with the control group. The differentially expressed proteins distributed their functions in reduction-oxidation reactions, DNA repair, cell cycle regulation, transporters and channels, and oxidative phosphorylation. Furthermore, heat shock protein 70 (HSP70), ATP-binding cassette transporter isoform B6 (ABCB6), and prohibitin (PHB) identified in this study may be closely related to chemoresistance and could serve as potential chemotherapeutic targets for NHL. Collectively, these results suggest that specific mitochondrial proteins are uniquely susceptible to alterations in abundance following exposure to ADR and carry implications for the investigation of therapeutic and prognostic markers. Further studies focusing on these identified proteins will be used to predict treatment response and reverse apoptosis resistance,and to explore drug-combination strategies associated with ADR for NHL therapy.

Salvage Chemotherapy in Follicular Non-Hodgkin's Lymphoma: Focus on Tolerability

Follicular lymphoma (FL) is typically characterized by repeated remissions and relapses, and many patients receive a number of therapeutic interventions during their disease course. Although treatment options are evolving rapidly, stem cell transplantation offers a potentially favorable impact on survival. In general, many patients with FL are not eligible for this approach by virtue of age and/or comorbid disease. Salvage chemotherapy consequently remains the mainstay of treatment, being individualized according to disease and patient characteristics, goals of therapy, and patient preference. Many of the cytotoxic agents used in relapsed FL are highly myelotoxic, leading to significant morbidity and mortality, including febrile neutropenia, hemorrhage, and impaired quality of life. Nausea and vomiting can also be problematic, particularly with regimens incorporating carmustine, cisplatin, and high-dose cyclophosphamide. Other acute toxicities include mucositis, alopecia, extravasation injuries, and neurotoxicity. Late toxicities can also occur, sometimes months or even years after the administration of antineoplastic agents. Acute myeloid leukemias, myelodysplastic syndromes, or solid tumors can occur after chemotherapy with alkylating agents. The cardiotoxic profile of anthracycline antibiotics is well recognized, and several agents, including carmustine and cyclophosphamide, can cause lung injury. Persistent neurotoxicity, nephrotoxicity, ototoxicity, and vascular toxicity have also been reported in association with chemotherapeutic agents used in patients with relapsed FL. Novel therapeutic strategies might allow patients to achieve longer remissions, potentially reducing lifetime exposure to repeated cycles of chemotherapy and their attendant toxicities. These could include the use of more efficient preparative and purging approaches in the transplantation setting or the administration of rituximab maintenance therapy after (immuno) chemotherapy induction or transplantation.

Multicenter phase II trial of immunotherapy with the humanized anti-CD22 antibody, epratuzumab, in combination with rituximab, in refractory or recurrent non-Hodgkin's lymphoma

PURPOSE

A multicenter, single-arm study examining efficacy and toxicity of epratuzumab combined with rituximab was conducted in patients with recurrent or refractory non-Hodgkin's lymphoma.

PATIENTS AND METHODS

Sixty-five patients were enrolled; 34 patients with follicular lymphoma (FL), 15 patients with diffuse large B-cell lymphoma (DLBCL), and 16 patients with other lymphomas. The patients had received a median of two prior therapies (range, 1 to 4); 23% had received rituximab. Epratuzumab was given at 360 mg/m2 intravenously over 60 minutes followed by infusion of 375 mg/m2 rituximab, weekly for 4 consecutive weeks.

RESULTS

Combination therapy was well tolerated without greater toxicity than rituximab alone. The objective response (OR) rate was 47% (30 of 64) in assessable patients (46%; 30 of 65 in all patients), being highest in FL (64%; 21 of 33) and DLBCL (47%; seven of 15), and with 24% (eight of 33) and 33% (five of 15) achieving complete response (CR) or complete response unconfirmed (CRu) in these two groups, respectively. Two of six patients with marginal zone lymphoma responded to treatment (one CR). There was a trend for the response rates to be higher in patients with low prognostic index scores (statistically significant with respect to the Follicular Lymphoma International Prognostic Index score in FL patients), with 12 FL patients and three DLBCL patients in groups 0 to 1 having OR (CR/CRu) rates of 83% (33%) and 100% (100%), respectively. The median duration of response was 16 months for FL, with five patients currently progression free for 18 months to 30 months, and 6 months for DLBCL, with two patients currently progression free for 12 months and 18 months.

CONCLUSION

Epratuzumab combined with rituximab was well tolerated, demonstrating promising antilymphoma activity that warrants additional study.

An in vitro model to study chemoresistance in non-Hodgkin's lymphoma patients over-expressing mutant p53

INTRODUCTION

P-Glycoprotein plays a major role in regulating the concentration of chemotherapeutic agents inside the cytoplasm of normal and cancerous cells. The present in vitro study has primarily focused on the evaluation of the chemosensitising drug model, verapamil, as a P-glycoprotein antagonist not only to overcome chemoresistance in non-Hodgkin's lymphoma (NHL) chemoresistant cells (p53(+) i.e. over-expressing p53 mutant protein NHL cells) but also to evaluate and suggest the use of the single cell gel electrophoresis (SCGE) assay in the clinical setting.

METHODS

Leucocytes from CHOP-chemoresistant NHL patients (p53(+) cells) were examined in the SCGE assay. Altered levels of DNA damage (tail moments) were determined by the assay not only in the leucocytes from clinical samples, but also in the Raji cell sub-lines (NHL model) which are also over-expressing p53 mutant protein. In addition, as a comparison, P-glycoprotein was examined in normal human leucocytes and Raji cells.

RESULTS

Verapamil increased the tail moments induced by doxorubicin in all cell types over-expressing p53 mutant protein.

DISCUSSION

The assay was successful for evaluating P-glycoprotein regulation. This suggests the applicability at the cellular level of the method as suitable for use in the clinical setting since it is reliable and could be used pre-clinically or perhaps instead of or alongside clinical trails. Cells from patients with a chemoresistant disease state or whose disease relapses subsequently could be treated with such novel experimental therapies in vitro to determine the necessity for the individual administration of a P-glycoprotein antagonist.

New treatment approaches to indolent non-Hodgkin's lymphoma

Disseminated indolent non-Hodgkin's lymphoma (NHL) is considered incurable with conventional chemotherapy regimens, and more than 50% of patients die within 5 years of their first relapse. Therefore, newer treatment approaches have been used to try to improve survival and ultimately provide a cure for patients with disseminated indolent NHL. The anti-CD20 monoclonal antibody rituximab has been extensively evaluated and is now an integral component of many treatment strategies. The activity of rituximab was first shown in the pivotal trial in patients with relapsed and refractory low-grade and follicular lymphoma. More recent studies have shown somewhat higher activity of rituximab when used first-line, with further improvements with maintenance therapy. Rituximab in combination with chemotherapy has been shown to achieve high response rates, and two prospective randomized studies from the German Low-grade Lymphoma Study Group have shown significantly higher response rates and longer survival for patients receiving rituximab concurrently with chemotherapy compared with those receiving chemotherapy alone. Further data from ongoing phase III studies are still needed to determine whether rituximab can help alter the natural history of indolent NHL, and longer follow-up of these patients will help determine the optimal role for rituximab in treatment of indolent NHL.

Phase I/II trial of epratuzumab (humanized anti-CD22 antibody) in indolent non-Hodgkin's lymphoma

PURPOSE

This single-center, dose-escalation study examines the safety, efficacy, and pharmacokinetics of epratuzumab (anti-CD22 humanized monoclonal antibody) in patients with recurrent indolent non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Patients had indolent NHL and recurrent disease after at least one chemotherapy regimen. Epratuzumab was administered intravenously at 120 to 1,000 mg/m2 over 30 to 60 minutes weekly for four treatments.

RESULTS

Fifty-five patients received epratuzumab and were assessable for safety; 51 patients were assessable for response. Patients were heavily pretreated (50% had at least four prior regimens) and 49% had bulky disease (> or = 5 cm). Epratuzumab was well tolerated, with no dose-limiting toxicity. Circulating B cells transiently decreased without significant effects on T cells or immunoglobulin levels. More than 95% of infusions were completed in approximately 1 hour. Mean serum half-life was 23 days. Across all dose levels and histologies, nine patients (18%; 95% confidence interval, 8% to 31%) achieved objective response, including three complete responses (CRs). All responses were in patients with follicular NHL: 24% of these patients responded, including 43% in the 360 mg/m2 dose group and 27% in the 480 mg/m2 dose group. No responses were observed in other indolent histologies. Median duration of objective response was 79.3 weeks (range, 11.1 to 143.3 weeks), with median time to progression for responders of 86.6 weeks by Kaplan-Meier estimate.

CONCLUSION

Epratuzumab was well tolerated at up to 1,000 mg/m2/wk (for 4 weeks) and had clinical activity. One third of responding patients achieved CR. A 43% objective response rate in follicular NHL patients treated at 360 mg/m2/wk indicates that this dose should be explored in additional studies.

Myeloablative therapy and bone marrow transplantation in Jehovah's Witnesses with malignancies: single center experience

Hematological malignancies in Jehovah's Witnesses are often difficult to cure since these patients deny transfusions. By a retrospective analysis, we report the possibility of treating some tumors, mostly hematological, with either autologous or allogeneic bone marrow transplantation (BMT) without blood support. Eight patients were evaluated, including lymphoma (two patients), acute lymphoblastic (one patient) and myeloblastic (one patient) leukemia, chronic lymphocytic leukemia (one patient), refractory anemia with blasts in transformation (one patient), chronic myeloid leukemia (one patient) and metastatic breast cancer (one patient). All patients experienced a severe cytopenia with no major side effects or life-threatening complications. We had four deaths: three from relapse and progression of the disease (at 5, 8 and 15 months after the stem cell infusion), and one from acute intestinal GVHD (at 2 months after the stem cell infusion). Four patients are in complete clinical remission (at 8, 10, 16 and 26 months after the stem cell infusion), and this was related to the disease outcome. We conclude that autologous and allogeneic BMT are feasible without the support of transfusions. We believe that this should be performed as soon as possible in the course of the disease.

Small Bowel Lymphoma

Treatment of small bowel lymphoma requires the expertise of medical and surgical subspecialists. The two most important factors that determine the optimal treatment are histology and staging of small bowel lymphoma. Other factors that may affect treatment include age, multiple areas of involvement, tumor size, and perforation. At present, the best treatment for gastrointestinal lymphoma (stage IE disease) is limited resection of the tumor, followed by postoperative radiotherapy. The cure rate is approximately 75% for stage IE patients, even for those with aggressive histologic types. Chemotherapy is reserved for advanced-staged tumors. In patients with regional nodal involvement or extranodal involvement confined to one side of the diaphragm (pathologic stage IIE disease), chemotherapy should be combined with radiation therapy. The best chemotherapy regimen depends on the histology of the tumor. For diffuse large B-cell lymphoma, the most frequently diagnosed subtype of non-Hodgkin's lymphoma (NHL), the CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisone) is still the gold standard. Clinical trials have been conducted evaluating the new monoclonal antibody rituximab, along with the CHOP regimen for primary NHL. Results have been promising. The use of rituximab in the treatment of extranodal lymphoma is still being evaluated. Low-grade lymphomas have a more indolent course and do not respond as well to combination chemotherapy agents as the high-grade tumors. Fludarabine alone or in combination with cyclophosphamide is effective as a first-line agent for patients with low-grade NHL. It has also been used to treat relapsed or refractory low-grade NHL. Some promising results have been reported using the chemoimmunotherapy agent rituximab alone or in combination with fludarabine for the treatment of low-grade NHL. However, clinical trials are still needed. In patients with nodal involvement on both sides of the diaphragm or other extranodal involvement such as bone marrow or liver (pathologic stages IIIE and IVE), the disease is managed primarily with combination chemotherapy. Radiation therapy is reserved for treatment of initially bulky tumor sites, treatment of residual disease following chemotherapy, or serious local problems. The disease can be controlled in 25% to 40% of patients with stage IIIE or IVE disease. As with stage IIE disease, the optimal chemotherapy regimen depends on the histologic subtype of NHL.

Apoptosis stimulating protein of p53 (ASPP2) expression differs in diffuse large B-cell and follicular center lymphoma: correlation with clinical outcome

ASPP2 interacts with the tumor suppressor protein p53, promotes damage-induced apoptosis, and can specifically stimulate p53 apoptotic function. Thus, ASPP2 may function as a tumor suppressor and/or play a role in the cellular response to cytotoxic injury. To explore the role of ASPP2 in human cancer, we determined ASPP2 expression in two lymphoma subtypes with differing clinical outcomes: diffuse large B-cell lymphoma (DLBCL) and follicular center lymphoma (FCL). A real-time reverse transcription-polymerase chain reaction (RT-PCR) assay was developed to detect ASPP2 mRNA. Sixty-one DLBCL and twenty-three FCL cases were analyzed and normalized ASPP2 levels were expressed relative to an mRNA standard. We found that ASPP2 mean expression strongly correlated with lymphoma subtype: DLBCL = 11.74 and FCL = 4.99 (p = 0.029, unpaired 2-tailed t-test). Importantly, ASPP2 expression was variable in DLBCL but not FCL (DLBCL-range, 0.04-94.6; FCL-range, 1.2-15.0). In these DLBCL cases, serum lactate dehydrogenase (LDH) was an independent predictor of survival with median survival in the high LDH group of 24 months and median survival not achieved in the normal-low LDH group (p = 0.014, Log-Rank Test). Mean ASPP2 levels trended toward an inverse correlation with LDH levels: High LDH, ASPP2 = 6.2; Normal-low LDH, ASPP2 = 18.2 (p = 0.074, unpaired 2-tailed t-test). In the DLBCL cases with ASPP2 levels > 7.8, only 10% (1/10) had a high LDH, in contrast to cases with ASPP2 levels < 7.8 in which 59% (26/44) had a high LDH (p = 0.011, Fisher Exact Test). Thus, low ASPP2 mRNA levels may correlate with poor clinical outcome in lymphoma which is consistent with the hypothesis that ASPP2 may play a role in tumor formation and/or sensitivity to cytotoxic agents. Larger studies as well as analysis of different tumor types are warranted.

AntiCD20 mAbs: modifying therapeutic strategies and outcomes in the treatment of lymphoma patients

The first monoclonal antibody for the treatment of cancer, rituximab, was approved 5 years ago and has had a remarkable impact on the treatment of non-Hodgkin's lymphomas. Additionally, it sparked a renewed interest in antibodies in general that has revitalized this field of research. Multiple antibodies for a variety of malignant and nonmalignant indications are being evaluated. Some are now approved for anticancer indications (rituximab, ibritumomab, trastuzumab, gemtuzumab, alemtuzumab) and others are completing the review process at US (FDA) and European (EMEA) regulatory agencies. The impact of antiCD20 antibodies, particularly rituximab and ibritumomab, is evident in the way treatment strategies and outcomes have changed for the lymphoma patient. Other unconjugated antibodies (including Hu1D10, epratuzumab and alemtuzumab) and conjugated antibodies (including radiolabeled tositumomab) are under evaluation.