From hepatitis C virus infection to B-cell lymphoma.

In addition to liver disorders, hepatitis C virus (HCV) is also associated with extrahepatic immune manifestations and B-cell non-Hodgkin lymphoma (NHL), especially marginal zone lymphoma, de novo or transformed diffuse large B-cell lymphoma and to a lesser extent, follicular lymphoma. Epidemiological data and clinical observations argue for an association between HCV and lymphoproliferative disorders. The causative role of HCV in NHL has been further supported by the response to antiviral therapy. Pathophysiological processes at stake leading from HCV infection to overt lymphoma still need to be further elucidated. Based on reported biological studies, several mechanisms of transformation seem however to emerge. A strong body of evidence supports the hypothesis of an indirect transformation mechanism by which sustained antigenic stimulation leads from oligoclonal to monoclonal expansion and sometimes to frank lymphoma, mostly of marginal zone subtype. By infecting lymphocytes, HCV could play a direct role in cellular transformation, particularly in de novo large B-cell lymphoma. Finally, HCV is associated with follicular lymphoma in a subset of patients. In this setting, it may be hypothesized that inflammatory cytokines stimulate proliferation and transformation of IgH-BCL2 clones that are increased during chronic HCV infection. Unraveling the pathogenesis of HCV-related B-cell lymphoproliferation is of prime importance to optimize therapeutic strategies, especially with the recent development of new direct-acting antiviral drugs.

A diachronic-comparative analysis for the identification of the most powerful prognostic index for localized diffuse large B-cell lymphoma.

BACKGROUND: In the rituximab era, the conventional International Prognostic index (IPI) lost at least in part its predictive power, while the National Comprehensive Cancer Network-IPI (NCCN-IPI) seems to be a new and valid prognosticator. However, it has not yet been evaluated in patients with localized disease and it has not been compared with the modified IPI (mIPI) of the pre-rituximab era. In order to evaluate the different prognosticators and to assess the importance of rituximab and radiotherapy (RT), we carried out the so far largest retrospective analysis of patients with localized diffuse large B-cell lymphoma (DLBCL). PATIENTS AND METHODS: We retrospectively assessed clinical and therapeutical data of 1405 patients treated in from 1987 to 2012 in 10 cancer centers in Italy and 1 in Austria. RESULTS: All patients underwent an anthracycline containing polychemotherapy and 254 additional rituximab. The median follow-up was 5.7 years (range 0.1-23 years). The 5-year overall survival (OS) was 75%, being significantly superior in those who underwent additional rituximab, while RT consolidation did not improve the outcome of those who received immunochemotherapy. Patients with extranodal disease benefited from the addition of rituximab, while RT did not improve OS of the immunochemotherapy subgroup. In the pre-rituximab era, the mIPI showed a better performance than the others. In rituximab-treated patients, the NCCN-IPI had the highest discriminant value and the 5-years OS varied significantly (P < 0.001) between the three risk groups and was 98% in low-risk patients, 82% in those with a low-intermediate risk and 57% among high-intermediate and high-risk cases. CONCLUSIONS: The NCCN-IPI is so far the best prognosticator for patients with localized DLBCL who underwent R-CHOP(-like). The addition of rituximab is indispensable regardless of the risk category and site of involvement, while the addition of RT should be reserved to those cases who are ineligible to rituximab.

Antiviral treatment in patients with indolent B-cell lymphomas associated with HCV infection: a study of the Fondazione Italiana Linfomi.

BACKGROUND: Tumor regression after antiviral therapy (AT) is in favor of an etiological role of hepatitis C virus (HCV) in non-Hodgkin's B-cell lymphomas (NHL). PATIENTS AND METHODS: We carried out a cohort study of 704 consecutive HIV-negative, HCV-positive patients with indolent NHL diagnosed and treated from 1993 to 2009 in 39 centers of the Fondazione Italiana Linfomi; 134 patients were managed with AT for lymphoma control. RESULTS: For entire cohort, 5-year overall survival (OS) was 78% [95% confidence interval (CI): 74%-82%] and 5-year progression-free survival (PFS) was 48% (95% CI: 44%-53%). In multivariate analysis, the use of AT during the patients' life had positive impact on OS. Forty-four of the 100 patients treated with first-line AT achieved a complete remission (CR) and 33 a partial response (PR). HCV-RNA clearance was achieved in 80 patients and was related to lymphoma response. At a median follow-up of 3.6 years, 5-year PFS was 63% (95% CI: 50%-73%). CR + PR rate was 85% with AT as second-line treatment. CONCLUSION: AT produces HCV-RNA clearance and consequent tumor regression in most patients with HCV-related indolent NHL. AT used at any time is associated with improved OS. Consequently, AT can be considered an option for patients with indolent lymphomas who do not need immediate cytoreductive treatment.

Early-stage diffuse large B cell lymphoma of the head and neck: clinico-biological characterization and 18 year follow-up of 488 patients (IELSG 23 study).

It is known that extranodal head and neck diffuse large B cell lymphomas (eHN-DLBCL) can affect various anatomical structures what is not well-known, however, is whether they differ in terms of clinical presentation and outcome. Clinical data of the multi-institutional series, the largest of its kind as yet, has been analysed with the aim of answering these open questions and providing long-term follow-up information. Data from 488 patients affected by stage I/II eHN-DLBCL was collected: 300 of the Waldeyer's Ring (WR), 38 of the parotid and salivary glands (PSG), 48 of the thyroid gland (TG), 53 of the nasal cavity and paranasal sinuses (NPS), 24 of the palate and oral cavity (POC) and 25 with more than one involved site. Different eHN-DLBCL arising have distinct characteristics at presentation. The intermediate high risk-modified IPI was 67 % in TG, 44 % in WR, 38 % in PSG and POC and 20 % in MS. The worst 5-year survival rate had TG-DLBCL (61 %) due to the 61 % of patients with a mIPI >1. The addition of radiotherapy (cRT) to remitters did not translate into a survival advantage (5-year disease-free survival of 67 % in the cRT group vs. 70 % in the other). Three of four central nervous system recurrences occurred in NPS-DLBCL. Survival of HN-DLBCL was inferior to nodal DLBCL. This study showed that eHN-DLBCL remitters have an inferior survival when compared to nodal DLBCL, and that the addition of cRT does not provide a survival advantage. Since the standard of care nowadays is chemo-immunotherapy, survival of these patients might have been improved.

Cost-Effectiveness of brexucabtagene autoleucel for relapsed/refractory mantle cell lymphoma.

Brexucabtagene autoleucel is a chimeric anti CD19 antigen receptor T-cell therapy that allows durable responses in relapsed/refractory (R/R) mantle cell lymphoma (MCL). The present study compared the clinical and economic outcomes of R/R MCL patients (pre-exposed to ibrutinib and chemoimmunotherapy) treated with brexucabtagene autoleucel versus Rituximab, bendamustine, cytarabine (R-BAC) in the Italian Healthcare System. A partitioned-survival model extrapolated survival and healthcare costs of R/R MCL patients over a lifetime horizon. Discounted and quality-adjusted life expectancy (QALY) was 6.40 versus 1.20 for brexucabtagene autoleucel versus R-BAC and lifetime costs were €411,403 versus €74,415, respectively, which corresponds to a cost of €64,798 per QALY gained. The results were highly sensitive to brexucabtagene autoleucel acquisition cost and to assumptions on long-term survival, therefore the cost-effectiveness of brexucabtagene autoleucel for patients with R/R MCL requires validation with longer follow-up data and in specific risk subgroups.

Primary plasma cell leukemia: a retrospective multicenter study of 73 patients.

BACKGROUND: Epidemiological and clinical information on primary plasma cell leukemia (pPCL) are rarely reported. The aims are to evaluate the clinical features, prognostic factors, and efficacy of treatments in pPCL. PATIENTS AND METHODS: A multicenter retrospective cohort study was carried out from January 2000 to December 2008 in 26 Italian hematology divisions. A total of 128 cases of plasma cell leukemia were collected, and 73 of them (57%) were classified as primary (male/female 43/30). RESULTS: Sixty-four patients had at least 1 sign of end-organ damage and 10 had extramedullary localization. One patient died early; of the remaining patients, 36 (50%) received anthracycline-based regimens as first-line therapy, 17 (24%) single alkylating agents, and 30 (42%) bortezomib or thalidomide as additional (n = 11) or unique treatments (n = 19). Twenty-three patients (31%) underwent autologous and/or allogeneic hematopoietic stem cell transplantation (HSCT). The median overall survival (OS) was 12.6 months; complete or partial response was achieved in 22 (30%) and 18 patients (25%), respectively; the median duration of response (DOR) was 16.4 months. HSCT patients had a longer OS and DOR (median 38.1 and 25.8 months, respectively) compared with nontransplanted patients (9.1 and 7.3 months, respectively, P < 0.001). OS was influenced by nonresponse to treatment, hypoalbuminemia, and HSCT. DOR was favorably influenced only by HSCT. CONCLUSIONS: pPCL is an aggressive disease with a poor prognosis and a low response rate to conventional therapy. HSCT is effective, increasing OS and DOR by 69% and 88%, respectively. The use of bortezomib and thalidomide may improve outcomes.

Concordant bone marrow involvement of diffuse large B-cell lymphoma represents a distinct clinical and biological entity in the era of immunotherapy.

In diffuse large B-cell lymphoma (DLBCL), the clinical and biological significance of concordant and discordant bone marrow (BM) involvement have not been well investigated. We evaluated 712 de novo DLBCL patients with front-line rituximab-containing treatment, including 263 patients with positive and 449 with negative BM status. Compared with negative BM disease, concordant BM adversely impacted overall and progression-free survival, independent of the International Prognostic Index (IPI) and cell-of-origin classification. Once BM is concordantly involved, poor prognosis was not associated with the extent of BM involvement. Conversely, patients with discordant BM showed favorable overall survival similar to stage I-II DLBCL. A BM-adjusted IPI, using three parameters: concordant BM involvement, age >60 years, and performance status >1, improves the risk stratification for DLBCL with positive BM. Intensive immunochemotherapy seemingly rendered survival benefit for patients with concordant BM, as did rituximab maintenance for the discordant BM group. Frequently revealing adverse clinical and molecular characteristics, patients with concordant BM demonstrated gene expression signatures relevant to tumor cell proliferation, migration and immune escape. In conclusion, clinical and biological heterogeneity is seen in DLBCL with positive BM but concordant BM involvement represents a distinct subset with unfavorable gene signatures, high-risk clinicopathologic features and poor prognosis.

Loss of PRDM1/BLIMP-1 function contributes to poor prognosis of activated B-cell-like diffuse large B-cell lymphoma.

PRDM1/BLIMP-1, a master regulator of plasma-cell differentiation, is frequently inactivated in activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL) patients. Little is known about its genetic aberrations and relevant clinical implications. A large series of patients with de novo DLBCL was effectively evaluated for PRDM1/BLIMP-1 deletion, mutation, and protein expression. BLIMP-1 expression was frequently associated with the ABC phenotype and plasmablastic morphologic subtype of DLBCL, yet 63% of the ABC-DLBCL patients were negative for BLIMP-1 protein expression. In these patients, loss of BLIMP-1 was associated with Myc overexpression and decreased expression of p53 pathway molecules. In addition, homozygous PRDM1 deletions and PRDM1 mutations within exons 1 and 2, which encode for domains crucial for transcriptional repression, were found to show a poor prognostic impact in patients with ABC-DLBCL but not in those with germinal center B-cell-like DLBCL (GCB-DLBCL). Gene expression profiling revealed that loss of PRDM1/BLIMP-1 expression correlated with a decreased plasma-cell differentiation signature and upregulation of genes involved in B-cell receptor signaling and tumor-cell proliferation. In conclusion, these results provide novel clinical and biological insight into the tumor-suppressive role of PRDM1/BLIMP-1 in ABC-DLBCL patients and suggest that loss of PRDM1/BLIMP-1 function contributes to the overall poor prognosis of ABC-DLBCL patients.

PO-03 - Khorana score and histotype predict the incidence of early venous thromboembolism (VTE) in Non Hodgkin Lymphoma (NHL). A pooled data analysis of twelve clinical trials of Fondazione Italiana Linfomi (FIL).

BACKGROUND: Recent studies show that the risk of VTE in NHL pts is similar to that observed in high risk solid tumors (i.e. pancreatic, ovarian cancer). VTE in NHL occurs in most cases within three months from diagnosis and can have substantial impact on treatment delivery and outcome as well as on quality of life. However few data are available on potential predictors. AIMS: To better clarify the epidemiology of early (within six months from treatment start) VTE in NHL we conducted a pooled data analysis of 12 clinical trials from FIL. Our analysis included basic demographic features, lymphoma-related characteristics as well the Khorana score (based on histology, BMI, platelets WBC and HB counts) which is extensively used in solid tumors to predict VTE risk. PATIENTS AND METHODS: From Jan. 2010 to Dec. 2014, all pts with B-cell NHL enrolled in prospective clinical trials from FIL for frontline treatment were included. For 9 studies study period included the entire trial population was included. The analyses were conducted based on CRFs as well as pharmacovigilance reports. VTE definition and grading was stated according to standard criteria of toxicity (CTCAE V4.0). Cumulative incidence of VTE from the study enrollment was estimated using the method described by Gooley et al. accounting for death from any causes as a competing risk. The Fine & Gray survival model was used to identify predictors of VTE among NHL pts. Factors predicting the grade of VTE were investigated using an ordinal logistic regression model. This pooled data analysis was approved by local IRB. RESULTS: Overall, 1,717 patients belonging to 12 studies were evaluated. Eight were phase I/II or II (25% of pts) and 4 phase III (75% of pts). M/F ratio was 1.41, Median age was 57, (IQ range (IQR) 49-66). Histologies were: DLCL-B 34%, FL 41%, MCL 18%, other 6%. Median BMI was 25 (IQR 22-28). Median Hb, WBC and platelets counts were 13g/dl) (IQR 11.5-14.2), 7.1*10^(9)/l (IQR 5.6-10.3), 224*10^(9)/l (IQR 169-298), respectively. 1189 pts were evaluable Khorana score: 58% low risk, 30% intermediate risk, 12% were high risk. Human erythropoetin support was given to 9% of patients. All pts received Rituximab. Planned therapeutic programs included ASCT in 27% of pts, conventional chemotherapy in 67% a conventional chemotherapy plus lenalidomide in 6%. Overall 59 any grade VTE episodes occurred in 51 pts (2.9%), including 21 grade III-IV VTE (18 pts). None was fatal. Median time from study enrolment to VTE was 63 days (IQR: 35-110). Considering death as a competitive event the 6 months cumulative incidence of VTE was 2,2% in low risk Khorana score, 4.5% (95%IC: 2.3-6.7) in intermediate and 6.6% (95%IC: 2.4-10.8) in high risk (p=0.012) (figure 1). Khorana score was predictive also for grade III-IV events as they were 0,7% (95% CI:0.1-1.4) in low risk and 2.0% (95% CI:0.8-3.3) in intermediate-high risk (p=0.048). The results were similar also after excluding lenalidomide containing studies. The Fine and Gray multivariate analyses, adjusted for age and stage, showed that Khorana score (intermediate risk adjHR=1.96; 95%IC: 0.84-4.56 and high risk adjHR=3.81; 95%IC: 1.51-9.58) and DLCL-B histotype (adjHR=2.58; 95% CI: 1.01-6.55) were independently associated to an increased risk of VTE. Moreover an ordinal logistical regression model indicated that the increase of one point in the Khorana score resulted in an increased risk of VTE (OR=1.85; 95% CI: 1.23-2.79). CONCLUSIONS: Our results suggest that DLCL-B histotype and Khorana score are predictors of VTE in NHL. The latter might become a simple and effective tool to assess the risk of VTE in NHL. Prospective validation including also patients not eligible for clinical trials is needed.

Primary testicular diffuse large B-cell lymphoma displays distinct clinical and biological features for treatment failure in rituximab era: a report from the International PTL Consortium.

Primary testicular diffuse large B-cell lymphoma (PT-DLBCL) is a unique subtype of DLBCL. The impact of rituximab on survival and patterns of treatment failure in PT-DLBCL patient remain controversial. We analyzed the clinical and biological feature of 280 PT-DLBCL cases, 64% of which were treated with rituximab-containing regimens. Although most (95%) patients achieved complete remission, a continuous risk of relapse was observed. Rituximab significantly reduced the cumulative risk of relapse (P=0.022) and improved both progression-free survival (PFS, P=0.012) and overall survival (OS, P=0.027) of PT-DLBCL patients (5-year PFS, 56% vs 36%; 5-year OS, 68% vs 48%). Central nervous system and contralateral testis were the most common sites of relapse, but other extranodal and nodal sites of relapse were also observed. Most cases of PT-DLBCL had a non-germinal center B-cell like (84%) immunophenotype and an activated B-cell like (86%) gene expression profile (GEP) subtype. The distinctive GEP signature of primary testicular lymphoma was relevant to tumor cell proliferation, dysregulated expression of adhesion molecules and immune response, likely accounting for the poor outcome. Accordingly, forkhead box P1 transcription factor (FOXP1) and T-cell leukemia/lymphoma 1 (TCL1) oncogenic activation were confirmed and predicted a significant trend of poor survival. This study provides valuable observations for better understanding of both clinical and biological features in PT-DLBCL patients.

Non-Hodgkin's lymphoma affecting the testis: is it curable with doxorubicin-based therapy?

This study was designed to determine response, outcome, and patterns of failure of patients with non-Hodgkin's lymphoma who presented with a testicular mass. Consecutive patients presenting to M.D. Anderson Cancer Center between 1969 and 1999 treated with doxorubicin-based regimens and with radiotherapy and/or intrathecal therapy were considered for this study. We identified 43 patients whose median age was 61 years. Ann Arbor stage (AAS) was I in 22 patients, II in 7 patients, III in 1 patient, and IV in 13 patients. All 43 patients had intermediate-grade lymphomas according to the Working Formulation, and all 31 tumors assessed immunophenotypically were large B-cell lymphoma according to the World Health Organization classification. The International Prognostic Index score was > or = 2 in 18 patients (42%). Thirty-four patients achieved complete remission, 19 of whom relapsed, and 5 failed initial therapy. At 10 years, progression-free survival (PFS) was 20% +/- 9% and survival was 33% +/- 9%. Progression-free survival for patients with AAS I/II vs. III/IV was 36% +/- 13% vs. 0%, respectively (P = 0.004). At 10 years, the actuarial probability of failure in the central nervous system was 34% +/- 9% and was 21% +/- 9% in contralateral testis. Using the intent-to-treat method, patients receiving cyclophosphamide/doxorubicin/ vincristine/prednisone (CHOP), with additional scrotal radiotherapy and intrathecal methotrexate, had a 5-year PFS of 91% +/- 9% vs. 30% +/- 15% vs. 41% +/- 12% for those receiving only one or neither of these additional modalities (P = 0.053). Doxorubicin-based regimens alone appear unable to cure most patients with lymphoma involving the testis, but CHOP with prophylactic intrathecal therapy and adjuvant scrotal radiotherapy appears promising. This should be confirmed with prospective clinical trials and longer follow-up.

Addition of rituximab to chemotherapy overcomes the negative prognostic impact of cyclin E expression in diffuse large B-cell lymphoma.

BACKGROUND: High levels of cyclin E (CCNE) are accompanied by shorter survival in cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone (CHOP)-treated diffuse large B-cell lymphomas (DLBCL), independent of the international prognostic index (IPI). Data on the prognostic role of CCNE in the 'rituximab (R)-era' are lacking. METHODS: To test reproducibility and applicability of observations from the 'pre-R era' to the 'R era', we examined the prognostic role of CCNE expression by immunohistochemistry in 1579 DLBCL on tissue microarrays (TMA); 339 patients were treated by CHOP and 635 by R-CHOP. RESULTS: 1209 samples (77%) were evaluable; failures were due to missing TMA punches and fixation artefacts. Mean expression of CCNE was 13% (0-85%); applying a cut-off of >16%, 382 DLBCL (31%) were positive. CCNE did not correlate with any of the known variables (IPI, primary site, cell of origin, proliferation, and BCL2- or C-MYC rearrangements). We were able to reproduce data suggesting an IPI- and response to therapy independent, negative prognostic impact of CCNE in CHOP-treated DLBCL patients: CCNE-positive cases had a median survival of 16 months compared with 57 months in negative ones (p=0.012). In R-CHOP-treated patients the prognostic impact of CCNE was abrogated and only IPI, cell of origin and response to therapy had a prognostic significance. CONCLUSIONS: Addition of R to CHOP overcomes the negative prognostic impact of CCNE in DLBCL. Thus, R not only prolongs survival in DLBCL but also serves a cautionary note that prognostic factors should not be transferred into the 'R era' without proper scientific studies.

Comprehensive gene expression profiling and immunohistochemical studies support application of immunophenotypic algorithm for molecular subtype classification in diffuse large B-cell lymphoma: a report from the International DLBCL Rituximab-CHOP Consortium Program Study.

Gene expression profiling (GEP) has stratified diffuse large B-cell lymphoma (DLBCL) into molecular subgroups that correspond to different stages of lymphocyte development-namely germinal center B-cell like and activated B-cell like. This classification has prognostic significance, but GEP is expensive and not readily applicable into daily practice, which has lead to immunohistochemical algorithms proposed as a surrogate for GEP analysis. We assembled tissue microarrays from 475 de novo DLBCL patients who were treated with rituximab-CHOP chemotherapy. All cases were successfully profiled by GEP on formalin-fixed, paraffin-embedded tissue samples. Sections were stained with antibodies reactive with CD10, GCET1, FOXP1, MUM1 and BCL6 and cases were classified following a rationale of sequential steps of differentiation of B cells. Cutoffs for each marker were obtained using receiver-operating characteristic curves, obviating the need for any arbitrary method. An algorithm based on the expression of CD10, FOXP1 and BCL6 was developed that had a simpler structure than other recently proposed algorithms and 92.6% concordance with GEP. In multivariate analysis, both the International Prognostic Index and our proposed algorithm were significant independent predictors of progression-free and overall survival. In conclusion, this algorithm effectively predicts prognosis of DLBCL patients matching GEP subgroups in the era of rituximab therapy.

High serum levels of B-lymphocyte stimulator are associated with clinical-pathological features and outcome in classical Hodgkin lymphoma.

B-lymphocyte stimulator (BLyS) acts as survival factor for B lymphocytes. As Hodgkin and Reed-Sternberg (HRS) cells express receptors through which BLyS promotes their growth and chemotherapy resistance, we investgated whether this molecule was increased in sera from patients with classical Hodgkin lymphoma (cHL) and whether it correlates with clinical-pathological features and outcomes. Enzyme-linked immunosorbent assay was used to measure soluble BLyS (sBLyS) in sera from 87 patients and 33 donors; higher levels were detected in patients (mean +/- standard error 4493.9 +/- 264.9 pg/ml vs. 2687.0 +/- 200.9 pg/ml; P < 0.0001). Levels above the median value (4242.0 pg/ml) were associated with age > or = 45 years (P = 0.042), advanced stages of disease (P = 0.005), systemic symptoms (P = 0.014) and extranodal involvement (P = 0.009). Five-year failure-free survival (FFS) of patients with sBLyS below or equal to median levels was 88.6% as compared to 65.1% of those with levels above the median (P = 0.009). Statistical analyses confirmed the prognostic significance of sBLyS (P = 0.046). When patients were analysed according to variables associated with high levels, sBLyS showed an independent predictive power in terms of FFS. Our findings support the involvement of BLyS in cHL pathogenesis. The association between high serum levels and an inferior FFS indicates that sBLyS is a possible prognostic predictor with a potential significance as a therapeutic target.

Distinctive natural history in hepatitis C virus positive diffuse large B-cell lymphoma: analysis of 156 patients from northern Italy.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) has been correlated to hepatitis C virus (HCV) infection in few series, but characteristics and outcome of these patients remain undefined. PATIENTS AND METHODS: We analyzed 156 previously untreated consecutive HCV-positive patients with DLBCL observed between 1994 and 2004 in three major institutions from northern Italy. RESULTS: Median age at presentation was 63 years and 8% of patients had DLBCL transformed from low-grade lymphomas. Spleen was the most frequently involved extranodal site, followed by liver and stomach. Treatment was delivered with cure-intent in 132 patients, while the remaining 24 patients received monochemotherapy or radiotherapy alone due to old age or seriously impaired hepatic function. Only five patients (4%) had to discontinue chemotherapy due to severe liver function impairment. The addition of rituximab did not seem to affect patients' tolerance to treatment. Five-year overall survival of the entire cohort was 72%, while 5-year progression-free survival (PFS) of the 132 patients treated with cure-intent was 51%. Hepatitis B virus co-infection, advanced Ann Arbor stage and nodal origin of the tumor resulted the strongest adverse prognostic factors. CONCLUSIONS: Patients with HCV-positive DLBCL share distinctive clinical features. Future studies should prospectively evaluate the association between HCV and aggressive lymphomas.

On the specificity of cytochrome c synthetase in recognition of the amino acid sequence of apocytochrome c.

Two forms of yeast cytochrome c synthetases with different specificities were resolved, one (synthetase I), solubilized from mitochondria or the cell debris with Triton X-100, recognizing not horse apocytochrome c but yeast apo-iso-1-cytochrome c as a substrate and the other (synthetase II) still bound with the particulate fraction from mitochondria after treatment with Triton, recognizing both horse and yeast apocytochromes c. The activity with labeled yeast apo-iso-1-cytochrome c as a substrate of cytochrome c synthetase I can be quantitatively inhibited by nonlabeled Candida krusei apocytochrome c and partially by nonlabeled tuna apocytochrome c but not by nonlabeled horse apocytochrome c indicating a specific amino acid sequence being recognized. However, an enzyme similarly solubilized from beef heart mitochondria recognized both horse apocytochrome c and yeast apo-iso-1-cytochrome c for attachment of heme. In view of the fact that the yeast synthetase II and the beef synthetase can both utilize either horse apocytochrome c or yeast apo-iso-1-cytochrome c as substrates, we suggest that these enzymes may also be involved in biosynthesis of cytochrome c1, that is, the ability to attach heme to apocytochrome c and apocytochrome c1 may have been conserved in eucaryotic cells, and that both synthetases may therefore be homologous.

Characterization of proteins by sequential isoelectric focusing on immobilized pH gradients and electrospray mass spectrometry.

The coupling of isoelectric focusing on immobilized pH gradients (IPG) with electrospray-mass spectrometry (ES-MS) was applied to the characterization of proteins according to two different and important properties, such as net surface charge and molecular mass. From a technical point of view, these methods are complementary, since ES-MS requires ion-free samples as usually supplied by isoelectric focusing on IPGs. This report describes the experiments carried out on model proteins to demonstrate the feasibility of the sequential application of these two techniques for the characterization of proteins. A minimum of 5 micrograms protein was needed for good signal by mass spectrometry. The following proteins were studied: myoglobin, truncated interleukin-6-mutein, recombinant cytochrome c551 and insulin-like growth factor I. Extraction from the IPG matrix was carried out in 70% acetonitrile/30% water/0.05% trifluoroacetic acid either by passive diffusion or by centrifugation through a 0.22 micron Amicon membrane, with protein recoveries of 80-85%.