Mutations of the p53 gene as a prognostic factor in aggressive B-cell lymphoma

Karyotyping of diffuse large B-cell lymphomas: loss of 17p is associated with poor patient outcome

BACKGROUND

Cytogenetic studies of patients with diffuse large B-cell lymphoma (DLBCL) have revealed a large spectrum of chromosomal abnormalities, some of which may be clinically relevant. We wanted to evaluate possible associations between commonly acquired chromosome aberrations and prognosis in a large cohort of patients.

METHODS

All patients with DLBCL treated at our center during 1999-2010 with an abnormal G-banding karyotype determined on cells short-term cultured from diagnostic biopsies were included. Detailed information on staging, treatment, and outcome was available for all patients.

RESULTS

Of the 110 patients available for analysis, there were 48 deaths and 27 relapses after a median follow-up of 4.5 yr. Eleven different chromosomal abnormalities were detected in more than ten percent of patients. Of those, only loss of 17p, including the TP53 tumor suppressor gene, was significantly associated with inferior long-term prognosis. Five year overall and progression-free survival frequencies were 32% and 27% for patients with loss of 17p and 67% and 59% in patients without this abnormality.

CONCLUSION

In a relatively large cohort of patients with DLBCL analyzed by chromosome banding, loss of 17p was the only chromosomal abnormality associated with inferior survival in uni- and multivariate analysis.

Serum level of soluble tumor necrosis factor receptor 2 is associated with the outcome of patients with diffuse large B-cell lymphoma treated with the R-CHOP regimen

BACKGROUND

Serum soluble tumor necrosis factor receptor 2 (sTNFR2) concentration predicted the clinical outcome of patients with aggressive non-Hodgkin's lymphoma including diffuse large B-cell lymphoma (DLBCL) treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) in our previous study. However, after rituximab (R) was introduced in clinical practice, R-CHOP replaced CHOP as the standard therapy for DLBCL.

PATIENTS AND METHODS

In this study, we re-evaluated the prognostic significance of serum sTNFR2 in 154 patients with DLBCL treated with R-CHOP.

RESULTS

Five-yr overall survival (5-yr OS) rates with sTNFR2 ≥20 ng/mL and <20 ng/mL were 29.2% and 83.3% (P < 0.0001), respectively, and the corresponding 5-yr progression-free survival (5-yr PFS) rates were 26.9% and 76.4% (P < 0.0001), respectively. A multivariate analysis revealed that serum sTNFR2 and complete remission (CR) were independent prognostic factors for both OS (CR: P < 0.0001, sTNFR2: P = 0.0001) and PFS (CR: P < 0.0001, sTNFR2: P = 0.0001). The prognosis of patients with poor risk groups according to the revised International Prognostic Index who also had high serum sTNFR2 was especially poor.

CONCLUSION

Serum sTNFR2 might be a powerful prognostic factor for patients with DLBCL in the rituximab era.

Mapping genetic alterations causing chemoresistance in cancer: identifying the roads by tracking the drivers

Although new agents are implemented to cancer therapy, we lack fundamental understandings of the mechanisms of chemoresistance, the main obstacle to cure in cancer. Here we review clinical evidence linking molecular defects to drug resistance across different tumour forms and discuss contemporary experimental evidence exploring these mechanisms. Although evidence, in general, is sparse and fragmentary, merging knowledge links drug resistance, and also sensitivity, to defects in functional pathways having a key role in cell growth arrest or death and DNA repair. As these pathways may act in concert, there is a need to explore multiple mechanisms in parallel. Taking advantage of massive parallel sequencing and other novel high-throughput technologies and base research on biological hypotheses, we now have the possibility to characterize functional defects related to these key pathways and to design a new generation of studies identifying the mechanisms controlling resistance to different treatment regimens in different tumour forms.

Clinical applications of BAC array-CGH to the study of diffuse large B-cell lymphomas

BAC array-CGH is a powerful method to identify DNA copy number changes (gains, amplifications and deletions) on a genome-wide scale, and to map these changes to genomic sequence. It is based on the analysis of genomic DNA isolated from test and reference cell populations, the differential labelling with fluorescent dyes and the co-hybridization with a genomic array. BAC array-CGH has proven to be a specific, sensitive, and reliable technique, with considerable advantages compared to other methods used for the analysis of DNA copy number changes. The application of genome scanning technologies and the recent advances in bioinformatics tools that enable us to perform a robust and highly sensitive analysis of array-CGH data, useful not only for genome scanning of tumor cells but also in the identification of novel cancer related genes, oncogenes and suppressor genes. Cytogenetic analysis provides essential information for diagnosis and prognosis in patients with hematologic malignancies such as lymphomas. However, the chromosomal interpretation in non-Hodgkin lymphoma (NHL) is sometimes inconclusive. Copy number aberrations identified by BAC array-CGH analyses could be a complementary methodology to chromosomal analysis. In NHL the genomic imbalances might have a prognostic rather than a diagnostic value. In fact, the diagnosis of NHL is based on pathological and molecular cytogenetics data. Furthermore genetic variations and their association with specific types of lymphoma development, and elucidation of the variable genetic pathways leading to lymphoma development, are important directions for future cancer research. Array-CGH, along with FISH and PCR, will be used for routine diagnostic purposes in near future.

Serum soluble interleukin-2 receptor (sIL-2R) level is associated with the outcome of patients with diffuse large B cell lymphoma treated with R-CHOP regimens

Serum concentration of soluble interleukin-2 receptor (sIL-2R) predicts the clinical outcome of patients with aggressive non-Hodgkin's lymphoma treated with the cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) regimen without rituximab. In the present study, we aim to re-assess the prognostic significance of serum sIL-2R for diffuse large B cell lymphoma (DLBCL) patients treated with CHOP plus rituximab and to assess sIL-2R with subtype of DLBCL, such as GCB type and non-GCB type. Two hundred and thirty-three patients with DLBCL were enrolled between December 2002 and March 2008. To evaluate serum levels of sIL-2R, venous blood samples were drawn from patients immediately before initiation of treatment. Serum sIL-2R was determined by sandwich enzyme-linked immunosorbent assay. The 5-year overall survival (OS) rates for patients with sIL-2R levels of ≥2,000 (110 cases) and <2,000 U/mL (123 cases) were 54.2% and 89.0% (P < 0.0001), respectively. Multivariate analysis using the proportional-hazards model revealed that serum sIL-2R (P = 0.0099) and extranodal involvement sites (P = 0.0392) were independent prognostic factors for OS and that clinical stage (P = 0.0168), performance status (P = 0.0181), sIL-2R (P = 0.0232), and LDH (P = 0.0316) were independent prognostic factors for progression-free survival in sIL-2R and every factor of the International Prognostic Index. Serum sIL-2R might be a useful prognostic factor for DLBCL patients in the rituximab era.

Rituximab in combination with CHOP chemotherapy for the treatment of diffuse large B cell lymphoma in China: a 10-year retrospective follow-up analysis of 437 cases from Shanghai Lymphoma Research Group

The purpose of the study is to evaluate the 10 years follow-up of the efficacy in Chinese patients receiving cyclophosphamide, doxorubicin/epirubicin, vincristine, and prednisone (CHOP) or rituximab plus CHOP (R-CHOP) regimen as the initial treatment for diffuse large B cell lymphoma (DLBCL). We have retrospectively analyzed 437 patients with DLBCL who were newly diagnosed and received CHOP or R-CHOP regimen in six university hospitals and closely followed up after the completion of treatment. For all patients, there were significant differences between R-CHOP and CHOP for overall survival (OS) (median follow-up 86 months, 84.1% vs 70.2%, p = 0.018) and progression-free survival (PFS) (81.5% vs 66.7%, p = 0.015), while elder patients (>60 years old) received higher OS (median follow-up 66 months, 80.7% vs 53.0%, p = 0.011). But for younger patients (≤60 years old), the treatments with rituximab did not demonstrate a significant effect on OS (85.5% vs 79.4%, p = 0.428). In the R-CHOP group, International Prognostic Index (IPI) distinguished three risk groups instead of four risk groups. But in the CHOP group, IPI still distinguished four risk groups. Furthermore, for 212 of 437 patients diagnosed with extranodal involvement DLBCL, R-CHOP regimen provided a longer OS than CHOP regimen did (OS, 89.9% vs 71.7%, p = 0.014). Moreover, patients with extranodal lymphoma had a significant longer survival in rituximab era (OS, 89.9% vs 79.2% for extranodal and nodal, respectively; p = 0.048). The results of this large-scale study suggested that R-CHOP provided a greater survival benefit in the initial treatment of DLBCL. As for the patients with extranodal lymphoma, R-CHOP was also a good choice as first-line treatment. Extranodal disease seems to be an independent good prognostic factor in rituximab era.

High resolution analysis of follicular lymphoma genomes reveals somatic recurrent sites of copy-neutral loss of heterozygosity and copy number alterations that target single genes

A multiplatform approach, including conventional cytogenetic techniques, BAC array comparative genomic hybridization, and Affymetrix 500K SNP arrays, was applied to the study of the tumor genomes of 25 follicular lymphoma biopsy samples with paired normal DNA samples to characterize balanced translocations, copy number imbalances, and copy-neutral loss of heterozygosity (cnLOH). In addition to the t(14;18), eight unique balanced translocations were found. Commonly reported FL-associated copy number regions were revealed including losses of 1p32-36, 6q, and 10q, and gains of 1q, 6p, 7, 12, 18, and X. The most frequent regions affected by copy-neutral loss of heterozygosity were 1p36.33 (28%), 6p21.3 (20%), 12q21.2-q24.33 (16%), and 16p13.3 (24%). We also identified by SNP analysis, 45 aberrant regions that each affected one gene, including CDKN2A, CDKN2B, FHIT, KIT, PEX14, and PTPRD, which were associated with canonical pathways involved in tumor development. This study illustrates the power of using complementary high-resolution platforms on paired tumor/normal specimens and computational analysis to provide potential insights into the significance of single-gene somatic aberrations in FL tumorigenesis.

Prognostic markers in diffuse large B-cell lymphoma: Keys to the underlying biology

Prognostic markers identify subgroups of patients with similar risk profiles, helping to guide clinical care. The addition of rituximab to conventional anthracycline-based chemotherapy has improved clinical outcomes for patients with diffuse large B-cell lymphoma (DLBCL). Studies suggest that rituximab eliminates or modulates the significance of some markers (eg, BCL6 or BCL2), whereas other previously unimportant markers may emerge as significant prognostic indicators in the setting of treatment that now includes rituximab. These changes in the prognostic profile are likely to reflect the impact of rituximab on survival pathways important to some groups of patients with DLBCL but not to other groups, and thereby may provide clues to the underlying biology of the disease. They also identify subgroups of patients likely to benefit most from rituximab therapy and those who seem to garner no advantage from its inclusion in their treatment. Studies of prognostic indicators in the context of modern therapy have the potential to identify new, rational therapeutic targets for this biologically diverse disease.

Systemic lupus erythematosus and increased risk to develop B cell malignancies: role of the p200-family proteins

Systemic lupus erythematosus (SLE), an autoimmune disease, develops at a female-to-male ratio of 10:1. Increased serum levels of type I interferons (IFN-alpha/beta) and induction of "IFN-signature" genes are associated with an active SLE disease in patients. Moreover, SLE patients exhibit three- to four-fold increase in the risk of developing malignancies involving B cells, including non-Hodgkin lymphoma (NHL) and Hodgkin's lymphoma (HL). Interestingly, homozygous mice expressing a deletion mutant (the proline-rich domain deleted) of the p53 develop various types of spontaneous tumors, particularly of B cell origin upon aging. The deletion is associated with defects in transcriptional activation of genes by p53 and inhibition of DNA damage-induced apoptosis. Notably, increased levels of the p202 protein, which is encoded by the p53-repressible interferon-inducible Ifi202 gene, in B cells of female mice are associated with defects in B cell apoptosis, inhibition of the p53-mediated transcription of pro-apoptotic genes, and increased lupus susceptibility. In this review we discuss how increased levels of the p202 protein (and its human functional homologue IFI16 protein) in B cells increase lupus susceptibility and are likely to increase the risk of developing certain B cell malignancies. A complete understanding of the molecular mechanisms that regulate B cell homeostasis is necessary to identify SLE patients with an increased risk to develop B cell malignancies.

Molecular targeted therapies for diffuse large B-cell lymphoma based on apoptosis profiles

Diffuse large B-cell lymphoma (DLBCL) is the most common type of adult non-Hodgkin lymphoma and is treated with chemotherapy in combination with rituximab. Despite this aggressive therapy, the disease is fatal in 30-40% of patients. Inhibition of the apoptosis signalling pathways is strongly related to response to chemotherapy and eventual clinical outcome. In order to survive, lymphoma cells depend on disruption of the apoptosis pathway by mutations in apoptosis inducing genes or by continuous expression of anti-apoptotic proteins. The development of molecules targeting these apoptosis inhibitors provides a very promising opportunity to specifically target tumour cells without toxicity to non-malignant cells in DLBCL patients. Sensitivity for most of these antagonists can be predicted based on biological markers, suggesting the possibility of pre-defining patients who will most likely benefit from these targeted therapies. Experimental therapies aimed at restoring the upstream apoptosis pathway or targeting apoptosis inhibitors are currently being tested in clinical trials and are expected to be effective particularly in chemotherapy-refractory DLBCL, providing hope for patients who are refractory to current therapies.

Expression of p21 protein predicts clinical outcome in DLBCL patients older than 60 years treated with R-CHOP but not CHOP: a prospective ECOG and Southwest Oncology Group correlative study on E4494

PURPOSE

To prospectively investigate the prognostic significance of p21 and p53 expression in diffuse large B-cell lymphoma in the context of the U.S. Intergroup trial comparing conventional cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy to rituximab-CHOP (R-CHOP) induction, with or without maintenance rituximab.

EXPERIMENTAL DESIGN

Immunohistochemical staining of 197 paraffin-embedded biopsy specimens was scored by an independent panel of experts.

RESULTS

The cyclin-dependent kinase inhibitor, p21, was expressed in 55% of cases examined. In a multivariable analysis adjusting for International Prognostic Index score and BCL2 status, p21 expression was a significant, independent, favorable predictive factor for failure-free survival (relative risk, 0.3; P = 0.001) and overall survival (relative risk, 0.3; P = 0.003) for patients treated with R-CHOP. Expression of p21 was not predictive of outcome for CHOP-treated patients. Only p21-positive cases benefited from the addition of rituximab to CHOP. Among p21-positive patients, treatment with R-CHOP was associated with a higher failure-free survival rate at 5 years compared with CHOP (61% versus 24%; P = 0.01). In contrast, no significant differences were detected in failure-free survival according to treatment arm for p21-negative patients. Expression of p53, alone or in combination with p21, did not predict for outcome in univariable or multivariable analyses.

CONCLUSIONS

In this study, p21 protein expression emerged as an important independent predictor of a favorable clinical outcome when rituximab was added to CHOP therapy. These data suggest that rituximab-related effects on lymphoma survival pathways may be functionally linked to p21 activity.

Characterization of genetic lesions in apoptosis-regulating and proliferation control genes in diffuse large B-cell non-Hodgkin's lymphoma

BACKGROUND

This study was conducted to analyze the frequency, expression patterns, and the impact of individual proteins BCL2, BCL6, and p53 on overall survival (OS) in adult, diffuse large B-cell lymphoma (DLBCL) patients. BCL2 gene was further investigated for potential alterations at the DNA level and correlated with OS.

MATERIALS AND METHODS

A total of 117 adult well-characterized DLBCL cases were included. The panel of antibodies comprised CD45, CD20, CD79a, CD3, BCL2, BCL6, and p53. PCR was also employed to correlate the events at the DNA level in BCL2.

RESULTS

The mean and median ages were 47.74 and 49 with a M:F ratio of 2.07:1. The incidence of BCL2, BCL6, and p53 expression was observed in 64.10%, 37.60%, and 52.13% of cases, respectively. Amplifiable quality DNA was available from 90 cases. BCL2/IGH translocation was found in 35/90 patients (38.88%) with 24 cases showing BCL2 (MBR)/IGH and 11 cases BCL2 (mcr)/IGH translocation. No association between BCL2 overexpression and BCL2 /IGH translocation was seen. Clinical data were available for 52 patients treated by CHOP therapy. It was found that patients with p53 overexpression had decreased overall survival (P = 0.0004) whereas BCL2, BCL6 expression, and BCL2/IGH translocation had no impact on overall survival.

CONCLUSION

Our data suggest that simple p53 protein expression by IHC at the time of diagnosis may help to identify high-risk patients, who may benefit with more aggressive and newer treatments in addition to standard CHOP.

Serum concentration of L-kynurenine predicts the clinical outcome of patients with diffuse large B-cell lymphoma treated with R-CHOP

PURPOSE

Introduction of rituximab has largely improved the prognosis of patients with diffuse large B-cell lymphoma(DLBCL). Such change in therapeutic outcome necessitates the identification of additional prognostic factors to conventional indexes that have been validated for CHOP without rituximab. Indoleamine 2,3-dioxygenase (IDO) exerts intense immunomodulatory effects because of enzymatic activities that catalyze the breakdown of the essential amino acid L-tryptophan. The activity of IDO can be estimated by measuring the serum concentration of L-kynurenine. Here, we investigated the role of L-kynurenine as a prognostic marker in R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) therapy.

EXPERIMENTAL DESIGN

Data from 73 consecutive patients treated with eight cycles of R-CHOP or R-THP (tetrahydropyranyl adriamycin)-COP between December 2002 and March 2007 were analyzed. L-kynurenine concentrations in serum samples obtained at admission were measured by high-performance liquid chromatography.

RESULTS

The median serum L-kynurenine level was 1.575 microm (range 0.537-9.588). The complete response (CR) rates of patients with L-kynurenine <1.5 and > or =1.5 microm were 83% and 61%, respectively (P < 0.05). The three-yr overall survival (OS) rates for patients with L-kynurenine <1.5 and > or =1.5 microm were 89% and 58%, respectively (P < 0.005). In addition, higher age, poor performance status, elevated serum lactate dehydrogenase, and unfavorable as well as revised International Prognosis Index were significantly worse factors for CR rate and OS. Multivariate analyses revealed only L-kynurenine as an independent prognostic factor for OS.

CONCLUSIONS

Serum L-kynurenine might be a novel prognostic factor to determine the treatment outcome of DLBCL with the R-CHOP regimen.

Lack of Prognostic Significance of BCL2 and p53 Protein Overexpression in Elderly Patients with Diffuse Large B-cell Non-Hodgkin's Lymphoma: Results from a Population-based Non-Hodgkin's Lymphoma Registry

The prognostic significance of age was studied in 372 patients with diffuse large B-cell non-Hodgkin's lymphoma, in relation to the prognostic factors of overexpressed BCL2 and p53 oncoprotein. Overexpression of BCL2 and p53 oncoprotein was defined when more than 50% of the tumor cells showed positive staining. The data were analyzed with respect to the age groups < 65 and > or = 65 years of age. There was a trend for BCL2 overexpression to occur significantly more often among patients older than 65 years of age (P = 0.065). Patients with BCL2 overexpression showed significantly inferior disease free survival rate, but only for patients younger than 65 years (log-rank test P = 0.0002), and the overexpression showed also an independent prognostic significance (P < 0.001). With respect to overexpressed p53 a significant difference was reached for complete remission rate (P = 0.01) and 5-year survival rate (log-rank test P = 0.04), again only for the younger age group. When the analyses were repeated for the older patients who had been treated adequately, the same lack of significance was found, both for BCL2 and p53. This study demonstrates that the negative prognostic value of overexpressed BCL2 and p53 protein is not of concern for patients older than 65 years of age. Among elderly patients the International Prognostic Index score seems the predominant risk factor for inferior prognosis.

Detection and Possible Prognostic Relevance ofp53Gene Mutations in Diffuse Large B-cell Lymphoma. An Analysis of 51 Cases and Review of the Literature

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma. Although the presence of p53 gene mutations has been considered as a bad prognostic feature in DLBCL, its clinical significance is still controversial. The aims of this study were: detect the presence of mutations in exons 5 to 9 of the p53 gene and correlate it to prognosis in DLBCL. Fifty-one DLBCL patients were enrolled in this study. Expression of p53 was evaluated by immunohistochemistry. The screening of p53 mutations was performed using PCR-SSCP methods. Cases showing a mobility shift on SSCP electrophoresis were analyzed by automatic sequencing. We could identify 8 missense mutations in 6 of 48 cases (12.5%). In addition, we found a known polymorphism at codon 213 and 2 instances of silent mutations. Of all mutations/polymorphisms found, 7 (64%) were localized in codons previously described as p53 hot spots in NHL cases. Of the remaining alterations (4 or 36%), 2 mutations were localized in codons previously described as hot spots for p53 in other tumors and 2 (codon 142 of the exon 5 and codon 195 of the exon 6), in codons not described as hot spots for p53 up to now. The presence of missense mutations in exons 5 to 9 of p53 gene had adverse impact on overall survival (P = 0.020). Cox's Regression Model identified that high-risk International Prognostic Index (IPI) and p53 gene mutations have independent negative impact on OS. Therefore, the association of IPI with cellular factors, such as p53 mutation, can be very helpful in deciding when we should indicate more aggressive therapies in patients with DLBCL, to somehow increase the chance of cure in these patients.

Primary breast lymphomas

The diagnosis, prognostic factors, and optimal management of primary breast lymphomas (PBL) is difficult. Seven patients recorded at the Geneva Cancer Registry between 1973–1998 were reviewed. Five patient had diffuse large B-cell lymphoma, one a follicular lymphoma and one a MALT-lymphoma. All patients had clinical and radiological findings consistent with breast cancer and underwent mastectomy, which is not indicated in PBL. Diagnosis should be established prior to operative interventions, as fine needle aspiration missed the diagnosis for one patient and intra-operative frozen sections for 3 patients in our study. Five-year and 10-year overall survivals were 57% and 15%, respectively. Of the 3 patients who died from PBL, 2 had tumors that were Bcl-2 positive but Bcl-6 negative. All 3 surviving patients have positive Bcl-2 and Bcl-6 immunostaining, which could be important prognostic factors if confirmed by a larger study.

Diffuse aggressive B-cell lymphomas

Diffuse aggressive B-cell lymphomas comprise a relatively common and increasingly diverse group of neoplasms. Newer modalities including gene expression profiling and an increasing panel of immunohistochemical markers have contributed to greater accuracy in defining these entities. Attention is paid not only to the neoplastic cells but also to the cellular and stromal milieu in which they proliferate. These distinctions may have therapeutic implications as well, with improved outcome related to newer and sometimes targeted therapies. At the same time there is increasing understanding of the overlap, which occurs in the grey zone between diffuse large B-cell lymphoma and Burkitt lymphoma as well as between diffuse large B-cell lymphoma and Hodgkin lymphoma. This review aims to provide practical insights in the correct identification and differential diagnosis of these lymphomas, with emphasis on the changes that have occurred with the publication of the 2008 World Health Organization updated classification.

Gene expression profiling in diffuse large B-cell lymphoma

Diffuse Large B cell lymphoma (DLBCL) is characterized by a markedly heterogeneous clinical course and response to therapy that is not appreciated with standard histopathologic and immunophenotypic evaluations. Analysis of global gene expression using DNA microarrays has the potential to improve the classification of lymphomas. Molecular profiling may allow the description of specific disease subtypes with similar clinical behavior and outcome. In addition, gene expression profiling has led to the discovery of new putative genes and a better understanding of aberrant signaling pathways. These insights may lead to the discovery of new targeted therapies. This review describes the progress that has been made in our understanding of DLBCL as a result of gene expression profiling.

Oncolytic rat parvovirus H-1PV, a candidate for the treatment of human lymphoma: In vitro and in vivo studies

The incidence of lymphomas developing in both immunocompetent and immunosuppressed patients continues to steadily increase worldwide. Current chemotherapy and immunotherapy approaches have several limitations, such as severe side toxicity and selection of resistant cell variants. Autonomous parvoviruses (PVs), in particular the rat parvovirus H-1PV, have emerged as promising anticancer agents. Although it is apathogenic in humans, H-1PV has been shown to infect and suppress various rat and human tumors in animal models. In this study, we demonstrate the capacity of H-1PV for efficiently killing, through necrosis, cell cultures originating from Burkitt's lymphoma (BL), while sparing normal B lymphocytes. The cytotoxic effect was generally accompanied by a productive H-1PV infection. Remarkably, parvovirus-based monotherapy efficiently suppressed established BL at an advanced stage in a severe combined immunodeficient (SCID) mouse model of the disease. The data show for the first time that an oncolytic parvovirus deserves further consideration as a potential tool for the treatment of some non-Hodgkin B-cell lymphomas, including those resistant to apoptosis induction by rituximab.

p37Ing1b regulates B-cell proliferation and cooperates with p53 to suppress diffuse large B-cell lymphomagenesis

The Inhibitor of Growth (ING) gene family encodes structurally related proteins that alter chromatin to regulate gene expression and cell growth. The initial member, ING1, has also been proposed to function as a tumor suppressor in human cancer based on its ability to suppress cell growth and transformation in vitro. Mouse Ing1 produces two proteins (p31 and p37) from differentially spliced transcripts. We have recently generated p37(Ing1b)-null mice and observed spontaneous follicular B-cell lymphomagenesis in this model to show that ING proteins can function in vivo as tumor suppressors. In this present report, we examine the role of p37(Ing1b) in the regulation of B-cell growth and explore the relationship between p37(Ing1b) and p53-mediated tumor suppression. Our results indicate that p37(Ing1b) inhibits the proliferation of B cells and follicular B cells regardless of p53 status, and loss of p53 greatly accelerates the rate of B-cell lymphomagenesis in p37(Ing1b)-null mice. However, in contrast to the highly penetrant follicular B-cell lymphomas observed in p37(Ing1b)-null mice, mice lacking both p37(Ing1b) and p53 typically present with aggressive diffuse large B-cell lymphomas (DLBL). Analysis of marker gene expression in p37(Ing1b)/p53 null tumors indicates that the double-null mice develop both nongerminal center and germinal center B-cell-like DLBL, and also documents up-regulation of nuclear factor-kappaB activity in p37(Ing1b)/p53-null B cells and B-cell tumors. These results confirm that p53 mutation is an important mechanistic step in the formation of diffuse large B-cell lymphomas and reveals a p53-independent role for Ing1b in suppressing B-cell tumorigenesis.

TP53 mutations in circulating free DNA from Egyptian patients with non-Hodgkin's lymphoma

BACKGROUND

P53 protein plays important role in the maintenance of genome stability in mammalian cells; it acts in many processes including cell-cycle checkpoint, DNA repair, apoptosis, and angiogenesis. Mutations of P53 have been reported as common mutations in solid tumours, including non-Hodgkin lymphoma, NHL, and have been implicated in drug resistance, aggression and poor prognosis. Chronic infection with hepatitis C, HCV, has been associated in some studies with increased risk of NHL. HCV is a widespread infection in the Egyptian population. Circulating free DNA (CFDNA) has been shown to be a good source of liver tissue-derived DNA in African and Asian patients with chronic liver disease or hepatocellular carcinoma, HCC. Our previous results have shown TP53 mutations in 5% of CFDNA and 10% of tumours of HCC, with underlying HCV.

OBJECTIVE

Since previous studies have shown p53 mutations in the DNAs extracted from the NH lymphoid tumours, we have assessed the presence of p53 mutations from exons 5 to 9 in CFDNA in patients with NHL, from Alexandria, Egypt, where HCV is highly prevalent, in a first attempt case-control preliminary study.

METHODS

CFDNA was extracted from sera of 20 cases with NHL and 20 negative control individuals. The retrieved serum DNAs were screened for TP53 mutations from exons 5 to 9 using direct sequencing and a PCR-restriction digestion analysis (RFLP). Concentrations of CFDNA were measured using Fluorometric assay.

RESULTS

Concentrations of CFDNA were significantly higher among NHL patients compared to the negative control individuals indicating a very high release or turn-over of DNA from the tumour into the blood stream among NHL patients. Mutations of p53 determined in NHL cases (30%) were of Arg-176 (1/20: 5%), Phe-238 (1/20: 5%), Ser-249 (2/20; 10%), Lys-249 (1/20: 5%) and Phe-250 (1/20: 5%). No mutations were detected among controls. However, Arg-213 polymorphism was found in 2 cases of NHL (10%) and in 1 case of controls (5%).

CONCLUSION

Our findings of higher DNA concentrations with some p53 mutations in CFDNA from patients with NHL that match the previous reported p53 mutations from tumour DNA may hold promises that CFDNA may serve as a convenient source of tumour-derived DNA to serve as a promising tool of a non-invasive, low-cost new strategy for earlier detection, diagnosis and follow up of the disease. A large-scale prospective study utilizing CFDNA and DNA from tumours of NHL patients will be required to validate this first trial of utilizing CFDNA from NHL patients.

Intraperitoneal dedifferentiated liposarcoma: A case report

Dedifferentiated liposarcoma is a variant of liposarcoma with a more aggressive course. Mutations of the p53 gene have been found in different types of soft tissue sarcoma. It is generally accepted that p53 mutations in human malignant tumors are often related to a poor prognosis. In our case, analysis of p53 gene mutation in tumor samples was performed. p53 gene mutation was observed in dedifferentiated tumor tissue samples but not in well-differentiated tumor tissue samples. It has been reported that p53 gene mutation occurs most commonly in the retroperitoneum and rarely in other anatomic locations. Herein we report a case of dedifferentiated liposarcoma located at intraperitoneum.

Serum-soluble interleukin-2 receptor (sIL-2R) is an extremely strong prognostic factor for patients with peripheral T-cell lymphoma, unspecified (PTCL-U)

PURPOSE

The aim of this study was to assess the prognostic factors of peripheral T-cell lymphoma, unspecified (PTCL-U).

PATIENTS AND METHODS

We retrospectively analyzed 30 cases fulfilling the criteria of PTCL-U defined by the World Health Organization classification. The patients were treated with 6-8 cycles of a CHOP or THP (pirarubicin)-COP regimen.

RESULTS

A high serum sIL-2R level (> or =2,000 U/ml) at onset was associated with a low complete remission rate. Patients with high sIL-2R had significantly lower survival rates (5 year, 15.1%) than those with low sIL-2R (<2,000 U/ml) (100%) (P < 0.005). Factors associated with worse overall survival in a univariate analysis were high sIL-2R (P < 0.005), high age (>60 years) (P < 0.05), poor performance status (P < 0.01) and poor international prognostic index (P < 0.05). No correlation was observed between sIL-2R and other markers. Multivariate analysis showed that only sIL-2R was a prognostic factor for overall survival (P < 0.01).

CONCLUSION

The results suggest that a high serum sIL-2R level predicts a poor prognosis in PTCL-U.

Structural profiles of TP53 gene mutations predict clinical outcome in diffuse large B-cell lymphoma: an international collaborative study

The purpose of this study is to correlate the presence of TP53 gene mutations with the clinical outcome of a cohort of patients with diffuse large B-cell lymphoma (DLBCL) assembled from 12 medical centers. TP53 mutations were identified in 102 of 477 patients, and the overall survival (OS) of patients with TP53 mutations was significantly worse than those with wild-type TP53 (P < .001). However, subsets of TP53 mutations were found to have different effects on OS. Mutations in the TP53 DNA-binding domains were the strongest predictors of poor OS (P < .001). Mutations in the Loop-Sheet-Helix and Loop-L3 were associated with significantly decreased OS (P = .002), but OS was not significantly affected by mutations in Loop-L2. A subset of missense mutations (His158, His175, Ser245, Gln248, His273, Arg280, and Arg282) in the DNA-binding domains had the worst prognosis. Multivariate analysis confirmed that the International Prognostic Index and mutations in the DNA-binding domains were independent predictors of OS. TP53 mutations also stratified patients with germinal center B cell-like DLBCL, but not nongerminal center B cell-like DLBCL, into molecularly distinct subsets with different survivals. This study shows the prognostic importance of mutations in the TP53 DNA-binding domains in patients with DLBCL.

Differential effects of novel tumour-derived p53 mutations on the transformation of NIH-3T3 cells

The p53 tumour suppressor gene is frequently mutated in human tumours and different tumour-derived mutations have varying effects on cells. The effect of a novel tumour-derived p53 mutation and two recently described mutations from South African breast cancer patients on the growth rate, colony formation, cell cycle arrest after irradiation and response to chemotherapeutic drugs was investigated. None of the p53 mutations had any significant effect on the inherent growth rate of the cells; however, contact inhibition of growth in two of the mutants was lost. These same two mutants formed colonies in soft agar, whereas the third mutant did not. All three of the mutants failed to show a G(1) cell cycle arrest after exposure to 7 Gy of [(60)Co] radiation, albeit to different degrees. Cells expressing the p53 mutants were either more sensitive to cisplatin and melphalan or more resistant than the untransfected cells, depending on the mutation. However, there was no difference in response to daunorubicin treatment. These results demonstrate that different p53 mutations exert varying biological effects on normal cells, with some altering checkpoint activation more effectively than others. The data also suggest that the nature of the p53 mutation influences the sensitivity to cytostatic drugs.

Detailed mapping of chromosome 17p deletions reveals HIC1 as a novel tumor suppressor gene candidate telomeric to TP53 in diffuse large B-cell lymphoma

Deletions in the short arm of chromosome 17 (17p) involving the tumor suppressor TP53 occur in up to 20% of diffuse large B-cell lymphomas (DLBCLs). Although inactivation of both alleles of a tumor suppressor gene is usually required for tumor development, the overlap between TP53 deletions and mutations is poorly understood in DLBCLs, suggesting the possible existence of additional tumor suppressor genes in 17p. Using a bacterial artificial chromosome (BAC) and Phage 1 artificial chromosome (PAC) contig, we here define a minimally deleted region in DLBCLs encompassing approximately 0.8 MB telomeric to the TP53 locus. This genomic region harbors the tumor suppressor Hypermethylated in Cancer 1 (HIC1). Methylation-specific PCR demonstrated hypermethylation of HIC1 exon 1a in a substantial subset of DLBCLs, which is accompanied by simultaneous HIC1 deletion of the second allele in 90% of cases. In contrast, HIC1 inactivation by hypermethylation was rarely encountered in DLBCLs without concomitant loss of the second allele. DLBCL patients with complete inactivation of both HIC1 and TP53 may be characterized by an even inferior clinical course than patients with inactivation of TP53 alone, suggesting a functional cooperation between these two proteins. These findings strongly imply HIC1 as a novel tumor suppressor in a subset of DLBCLs.

Mutations in the DNA-binding codons of TP53, which are associated with decreased expression of TRAILreceptor-2, predict for poor survival in diffuse large B-cell lymphoma

Mutations of the TP53 tumor suppressor gene have been associated with poor survival in some series of diffuse large B-cell lymphoma (DLBCL) but not in other studies. The purpose of this study was to identify the frequency of TP53 alterations (mutations or deletions), characterize the gene expression of mutant/deleted cases, and determine the effects of mutations on survival. In a series of DLBCL that had previous gene expression profiling, we identified 24 mutations in 113 cases (21%). There was no difference in the frequency of mutations in the molecular subgroups of DLBCL. Twelve (50%) of the 24 cases had mutations localized to the DNA-binding codons in the core domain of TP53. The presence of any TP53 mutation correlated with poor overall survival (OS; P = .044), but DNA-binding mutations were the most significant predictor of poor OS (P < .001). Multivariate analysis confirmed that the International Prognostic Index, tumor size, and TP53 DNA-binding mutations were independent predictors of OS. Gene expression analysis showed that TRAILreceptor-2 (DR5) was the most differentially underexpressed gene in the TP53 mutated cases. Investigation is warranted into targeted therapy toward TRAIL receptor-2, to potentially bypass the adverse effect of mutated TP53 in DLBCL.

Mutation of the p53 tumour suppressor gene and overexpression of its protein in 62 Japanese non-Hodgkin's lymphomas

To clarify whether p53 mutation could be involved in the pathogenesis of various subtypes of lymphoma, we investigated 62 Japanese cases of non-Hodgkin's lymphomas (NHLs) for p53 gene mutations and their relationship with the expression of p53 protein. Mutations in exons 5-9 of the p53 gene were screened for using the non-isotopic RNase cleavage assay (NIRCA) and confirmed by direct sequencing, followed by immunohistochemical analysis for p53 protein. Missense and/or nonsense mutations of p53 were detected in 3 (10.7%) of 28 diffuse large B-cell lymphomas (DLBLs) and 2 (15.4%) of 13 T-cell NHLs (15.4%). A single missense mutation at codon 157 (Val to Phe) in exon 5 and at codon 273 (Arg to Pro) in exon 8 was found respectively in 2 DLBLs and in one peripheral T-cell lymphoma (unspecified). In these 3 cases harbouring a missense mutation, overexpression of p53 protein was observed in more than 80% of tumour cells. Double transversion mutations comprising of a missense mutation at codon 167 (Gln to His) in exon 5 and a nonsense mutation at codon 183 (Ser to stop codon) in exon 5 were detected in one DLBL that had apparently transformed from follicular lymphoma and in one advanced adult T-cell lymphoma (ATL). In these two cases harbouring p53 nonsense mutation, no cells positive for p53 protein immunostaining were detected, as well as lymphomas without p53 mutation.

Missense mutation with/without nonsense mutation of the p53 gene is associated with large cell morphology in human malignant lymphoma

Mutations in p53 gene exons 5-9 were studied in 44 non-Hodgkin's lymphomas (NHL) consisting of 35 B-NHL and 9 T-NHL. Missense mutations were found in two diffuse large B-cell lymphomas (DLBL) and one peripheral T-cell lymphoma (unspecified). Double transversion missense and nonsense mutations were detected in one DLBL and one adult T-cell leukemia/lymphoma. Silent mutations were found in two DLBL. Detailed histomorphological study showed that cases harboring p53 missense mutation with/without nonsense mutation tended to have larger nuclei with much more prominent nucleoli. Cytomorphometric analysis was therefore conducted by measuring the gross area of 100 lymphoma cell nuclei in 44 cases and the results were compared between lymphomas harboring p53 missense mutation with/without nonsense mutation and lymphomas harboring p53 silent mutation or lacking mutation. It was found that the lymphomas harboring p53 missense mutation with/without nonsense mutation had a highly significantly larger nuclear gross area than lymphomas with silent p53 mutation or lacking mutation (two-sample t-test, P < 0.00001; Exact Wilcoxon rank-sum test, P < 0.00001). This result suggests that p53 mutation might induce enlargement of neoplastic cell nuclei by some molecular mechanism.

Predicting the outcome in non-Hodgkin lymphoma with molecular markers

The World Health Organization classification divides non-Hodgkin lymphomas into B-cell, T-cell and natural killer-cell lymphomas. They are heterogeneous in epidemiology, histopathology and outcome. Clinical prognostic indices rely only on patient factors and staging. Molecular prognostic markers reflect the intrinsic lymphoma biology, measure tumour load and may provide novel therapeutic targets. Lymphomagenesis involves mutations, deletions or dysregulations of genes critical in the control of cell cycle and apoptosis, which are in turn prognostically important. Genome-wide gene expression profiling, either by allowing lymphomas to be classified according to different stages of lymphoid maturation, or by defining specific gene expression signatures, is also of prognostic significance. In lymphomas where viral infections of the neoplastic cells occur, quantification of viral copies is a surrogate marker for tumour load and hence prognosis. Molecular markers together with patient and clinicopathological features will provide more accurate prognostic models for risk stratification, in order to improve treatment outcome.

Breast cancer prognostication and prediction in the postgenomic era

Expanding knowledge, together with implementation of new techniques, has fuelled the area of translational medical research aiming at improving prognostication as well as prediction in cancer therapy. At the same time, new discoveries have revealed a biological complexity we were unaware of only a decade ago. Thus, we are faced with novel challenges with respect to how we may explore issues such as prognostication and predict drug resistance in vivo. While microarray analysis exploring expression of thousands of genes in concert represents a major methodological advancement, discoveries such as the finding of different mechanisms of epigenetic silencing, intronic mutations, that most gene transcripts in the human genome are subject to alternative splicing and that hypersplicing seems to be a tumour-related phenomenon, exemplifies a complex pathology that may not be explored with use of single analytical methods only. This paper discusses clinical settings for studying drug resistance in vivo together with a discussion of contemporary biology in this field. Notably, each individual parameter which has been found correlated to drug resistance in vivo so far represents either a direct drug target or a factor involved in DNA repair or apoptosis. On the basis of these findings, we suggest drug resistance may be explored on the basis of upfront biological hypotheses.

Frequent DNA Methylation but not Mutation of the ID4 Gene in Malignant Lymphoma

ID4 is a member of the inhibitor of DNA binding (ID) family, and inhibits the binding of basic helix-loop-helix transcription factors to DNA. In some malignant tumors, ID4 is inactivated by promoter hypermethylation, and is thought to be a candidate tumor suppressor gene (TSG). We have found that the promoter region of the ID4 gene is frequently methylated in lymphoid cell lines (100%, 9/9), primary diffuse large B-cell lymphoma (95%, 19/20), and follicular lymphoma (100%, 10/10). Somatic mutation of the ID4 gene was also examined, and no mutations were found. These findings suggest that the ID4 gene might be inactivated by DNA hypermethylation, and may function as a TSG in malignant lymphoma.

Promoter hypermethylation of the DNA-repair gene O6-methylguanine-DNA methyltransferase and p53 mutation in diffuse large B-cell lymphoma

The gene for the DNA-repair enzyme O6-methylguanine-DNA methyltransferase (MGMT), which is closely related with cellular sensitivity to alkylating agents, is inactivated by promoter hypermethylation in several human cancers, including malignant lymphoma. Promoter hypermethylation of the MGMT gene is a favorable prognostic factor in diffuse large B-cell lymphoma (DLBCL). Although inactivation of the MGMT gene is closely related to p53 gene mutations in several cancers, the relationship between p53 gene mutation and MGMT inactivation in malignant lymphoma has not been thoroughly examined. We studied the correlation between MGMT hypermethylation and p53 mutation in DLBCL and their impacts on patient prognosis. In a retrospective cohort study, we used a methylation-specific polymerase chain reaction technique to analyze the methylation status of the promoter region of the MGMT gene in 116 DLBCL patients who received cyclophosphamide as part of multidrug combination chemotherapies. Denaturing high-performance liquid chromatography and direct sequencing were used to search for p53 gene mutations in exons 5 through 9 in 96 of the 116 samples. Disease-free survival and overall survival were estimated by the Kaplan-Meier method. Multivariate survival analyses were performed with the Cox proportional hazards model. Forty-five (38.8%) of 116 DLBCL patients showed MGMT promoter hypermethylation. The presence of MGMT hypermethylation was associated with better overall survival (P = .036). MGMT promoter hypermethylation was a prognostic factor that was independent of established prognostic factors, such as age, disease stage, serum lactic dehydrogenase level, and the number of extranodal disease sites (hazard ratio, 2.43; 95% confidence interval, 1.28-4.61; P = .007). p53 mutations were detected in 19 (19.8%) of 96 patients and were identified as a risk factor in the complete remission rate and overall survival (P = .0040, and P = .027, respectively). A correlation between MGMT hypermethylation and p53 mutation or p53 G:C-to-A:T mutation was not observed (P = .88, and P = .31, respectively). MGMT promoter hypermethylation and p53 mutation are useful prognostic markers in DLBCL. The impact of MGMT inactivation on p53 mutation in DLBCL is unclear.

Drug resistance in diffuse large B-cell lymphoma

Despite significant advances in the treatment of diffuse large B-cell lymphoma (DLBCL), drug resistance remains a major cause of treatment failure. Early strategies to improve outcome were mostly empiric or relied on classical mechanisms of drug resistance and were largely unsuccessful. More recent approaches have been aided by an understanding of the molecular pharmacology of drug action and tumor biology. Microarray profiling in particular has provided important insights into the complex biology of DLBCL and has led to a molecular taxonomy based on cell of origin and pathways of lymphomagenesis. It is now recognized that drug resistance is a complex and dynamic process related to cell cycle and apoptotic pathways, cellular differentiation, and the microenvironment. Drugs that target potential pathways of drug resistance, such as nuclear factor kappaB (NFkappaB), cyclin-dependent kinases (CDKs), and BCL-2 have entered clinical trials. However, the complexity of drug resistance requires that future clinical trials incorporate molecular translational endpoints to help identify the biologic basis of treatment failure.

Serum-soluble tumor necrosis factor receptor 2 (sTNF-R2) level determines clinical outcome in patients with aggressive non-Hodgkin's lymphoma

BACKGROUND

Recently investigators have worked to identify prognostic factors in non-Hodgkin's lymphoma (NHL) so an appropriate therapeutic plan can be put in action. The aim of the present study was to assess the prognostic significance of serum soluble tumor necrosis factor receptor (sTNF-R) 2 in aggressive NHL.

METHODS

One hundred and ten consecutive patients with aggressive NHL who were previously untreated (diffuse large B-cell lymphoma; 94, peripheral T-cell lymphoma; 16) were prospectively enrolled in this study between 1997 and 2002. The patients were treated with 6-8 cycles of CHOP or THP-COP regimens.

RESULTS

High serum sTNF-Rs level was associated with some poor prognostic factors and low complete remission rate. Patients with high sTNF-R1 (4 ng/mL and over) and sTNF-R2 (15 ng/mL and over) at onset had significantly lower survival rates (5 yr: 19%, 19%) than those with low sTNF-R1 (under 4 ng/mL) and sTNF-R2 (under 15 ng/mL) (62% and 69%), respectively (P < 0.0005 and 0.0001). Multivariate analysis employing sTNF-R2 and some conventional prognostic factors demonstrated that a combination of sTNF-R2 and performance status, and that of sTNF-R2, sIL-2R, and LDH were significant prognostic factors for poor overall survival and for poor event-free survival, respectively. In addition, we attempted to use sTNF-R2 in combination with the international prognostic index (IPI). The patients in the high risk group and those with high sTNF-R2 in the low-intermediate (LI)/high-intermediate (HI) risk group had significantly lower survival rates than the patients in the low risk group and those with low sTNF-R2 in LI/HI risk group (P < 0.0001).

CONCLUSIONS

The results suggest that a high serum sTNF-R2 level predicts a poor prognosis in aggressive NHL and may be a useful biomarker for selecting appropriate treatment when used in combination with the IPI.

CASPAR: a hierarchical bayesian approach to predict survival times in cancer from gene expression data

MOTIVATION

DNA microarrays allow the simultaneous measurement of thousands of gene expression levels in any given patient sample. Gene expression data have been shown to correlate with survival in several cancers, however, analysis of the data is difficult, since typically at most a few hundred patients are available, resulting in severely underdetermined regression or classification models. Several approaches exist to classify patients in different risk classes, however, relatively little has been done with respect to the prediction of actual survival times. We introduce CASPAR, a novel method to predict true survival times for the individual patient based on microarray measurements. CASPAR is based on a multivariate Cox regression model that is embedded in a Bayesian framework. A hierarchical prior distribution on the regression parameters is specifically designed to deal with high dimensionality (large number of genes) and low sample size settings, that are typical for microarray measurements. This enables CASPAR to automatically select small, most informative subsets of genes for prediction.

RESULTS

Validity of the method is demonstrated on two publicly available datasets on diffuse large B-cell lymphoma (DLBCL) and on adenocarcinoma of the lung. The method successfully identifies long and short survivors, with high sensitivity and specificity. We compare our method with two alternative methods from the literature, demonstrating superior results of our approach. In addition, we show that CASPAR can further refine predictions made using clinical scoring systems such as the International Prognostic Index (IPI) for DLBCL and clinical staging for lung cancer, thus providing an additional tool for the clinician. An analysis of the genes identified confirms previously published results, and furthermore, new candidate genes correlated with survival are identified.

A phase I/II study examining pentostatin, chlorambucil, and theophylline in patients with relapsed chronic lymphocytic leukemia and non-Hodgkin's lymphoma

In an attempt to exploit bcl-2 overexpression and aberrant p53 function, two frequently encountered aberrations that predict marked treatment resistance and worse prognosis in patients with chronic lymphocytic leukemia (CLL) and non-Hodgkin's lymphoma (NHL), we combined theophylline, pentostatin, and chlorambucil at two dose levels (cohort I: 30 mg/m(2); cohort II: 20 mg/m(2)) on a 21-day cycle for up to six courses. We employed a phase I/II design to determine feasibility, define the maximum tolerated dose (MTD), and explore the impact of biologic modulation on response and time to progression (TTP) in 20 patients with relapsed or refractory CLL and NHL. Eight patients were enrolled in cohort I. They demonstrated a response rate (RR) of 28% and a 16.5-month TTP after receiving a median of two cycles. A 50% RR was observed in this cohort when patients with adverse histologies were excluded. Because of myelotoxicity, this dose level defined the MTD, and de-escalation occurred. All 12 patients in cohort II received 20 mg/m(2) chlorambucil. A 50% RR and an 18-month TTP were observed after a median of 5.5 cycles. An RR of 47% and a complete remission (CR) of 5% were observed for the entire group, although responses and TTP varied greatly by histology. Significant activity was observed in patients with B-cell CLL and follicular lymphoma (FL). RR and TTP for fludarabine-sensitive/naïve and fludarabine-refractory (FR) B-cell CLL patients were 66 vs 25% and 20 vs 8.5 months, respectively. Both FL patients responded (one with partial remission and one with CR), with a 22.5-monthly median TTP. For responding patients, median TTP and overall survival (OS) was 21 and 69 months, respectively, compared to a median TTP of 2 months and an OS of 13.5 months for nonresponders. The combination of pentostatin, chlorambucil, and theophylline is the active regimen in patients with FL and B-cell CLL.