Do Double-Expressor High-Grade B-Cell Lymphomas Really Need Intensified Treatment? A Report from the Real-Life Series of High-Grade B-Cell Lymphomas Treated with Different Therapeutic Protocols at the Institute of Oncology Ljubljana.

High-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements are known for their aggressive clinical course and so are the ones with MYC and BCL2 protein overexpression. The optimal therapy for these lymphomas remains to be elucidated. A retrospective analysis of all diffuse large B-cell lymphomas and high-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements diagnosed between 2017 and 2021 at the Institute of Oncology Ljubljana, Slovenia, has been performed. Only patients with double-expressor lymphoma (DEL), double-hit lymphoma (DHL), or triple-hit lymphoma (THL) were included. Demographic and clinical parameters were assessed, as well as progression-free survival (PFS) and overall survival (OS). In total, 161 cases out of 309 (161/309; 52,1%) were classified as DEL. Sixteen patients had DHL, MYC/BCL2 rearrangement was observed in eleven patients, and MYC/BCL6 rearrangement was observed in five patients. Five patients were diagnosed with THL. Out of 154 patients (according to inclusion/exclusion criteria) included in further evaluation, one-hundred and thirty-five patients had double-expressor lymphoma (DEL), sixteen patients had DHL, and three patients had THL. In total, 169 patients were treated with R-CHOP, 10 with R-CHOP and intermediate-dose methotrexate, 19 with R-DA-EPOCH, and 16 with other regimens. The median follow-up was 22 months. The 5-year OS for the whole DEL group was 57.1% (95% CI 45.9-68.3%) and the 5-year PFS was 76.5% (95% CI 72.6-80.4%). The log-rank test disclosed no differences in survival between treatment groups (p = 0.712) while the high-risk international prognostic index (IPI) carried a significantly higher risk of death (HR 7.68, 95% CI 2.32-25.49, p = 0.001). The 5-year OS for DHL patients was 32.4% (95% CI 16.6-48.2%) while all three TH patients were deceased or lost to follow-up. Our analyses of real-life data disclose that the R-CHOP protocol with CNS prophylaxis is a successful and curative treatment for a substantial proportion of DEL patients.

Correlation of t(14;18) translocation breakpoint site with clinical characteristics in follicular lymphoma.

BACKGROUND: t(14;18)(q32;q21) translocation is an important genetic feature of follicular lymphoma resulting in antiapoptotic B-cell lymphoma 2 (BCL2) protein overexpression. On chromosome 18 breakpoint-site variation is high but does not affect BCL2. Breakpoint most commonly occurs at major breakpoint region (MBR) but may happen at minor cluster region (mcr) and between MBR and mcr at 3'MBR and 5'mcr. The aim of this study was to analyze the correlation of t(14;18)(q32;q21) breakpoint site with clinical characteristics in follicular lymphoma. PATIENTS AND METHODS: We included patients diagnosed with follicular lymphoma who received at least 1 cycle of systemic treatment and had the t(14;18)(q32;q21) translocation detected by polymerase chain reaction (PCR) at MBR, mcr or 3'MBR prior to first treatment. Among patients with different breakpoints, sex, age, disease grade, stage, B-symptoms, follicular lymphoma international prognostic index (FLIPI), presence of bulky disease, progression free survival and overall survival were compared. RESULTS: Of 84 patients, 63 had breakpoint at MBR, 17 at mcr and 4 at 3'MBR. At diagnosis, the MBR group had a significantly lower disease stage than the mcr group. Although not significant, in the MBR group we found a higher progression-free survival (PFS) and overall survival (OS), lower grade, age, FLIPI, and less B-symptoms. CONCLUSIONS: Compared to patients with mcr breakpoint, those with MBR breakpoint seem to be characterised by more favourable clinical characteristics. However, a larger study would be required to support our observation.

Molecular Mechanisms of Gastrointestinal Stromal Tumors and Their Impact on Systemic Therapy Decision.

Gastrointestinal stromal tumors (GISTs) are soft tissue sarcomas that mostly derive from Cajal cell precursors. They are by far the most common soft tissue sarcomas. Clinically, they present as gastrointestinal malignancies, most often with bleeding, pain, or intestinal obstruction. They are identified using characteristic immunohistochemical staining for CD117 and DOG1. Improved understanding of the molecular biology of these tumors and identification of oncogenic drivers have altered the systemic treatment of primarily disseminated disease, which is becoming increasingly complex. Gain-of-function mutations in KIT or PDGFRA genes represent the driving mutations in more than 90% of all GISTs. These patients exhibit good responses to targeted therapy with tyrosine kinase inhibitors (TKIs). Gastrointestinal stromal tumors lacking the KIT/PDGFRA mutations, however, represent distinct clinico-pathological entities with diverse molecular mechanisms of oncogenesis. In these patients, therapy with TKIs is hardly ever as effective as for KIT/PDGFRA-mutated GISTs. This review provides an outline of current diagnostics aimed at identifying clinically relevant driver alterations and a comprehensive summary of current treatments with targeted therapies for patients with GISTs in both adjuvant and metastatic settings. The role of molecular testing and the selection of the optimal targeted therapy according to the identified oncogenic driver are reviewed and some future directions are proposed.

CD56-positive diffuse large B-cell lymphoma: comprehensive analysis of clinical, pathological, and molecular characteristics with literature review.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. The expression of CD56 in DLBCL is highly unusual. Little is known about its incidence and clinical importance. So far, no genetic profiling was performed in CD56 positive DLBCL. PATIENTS AND METHODS: Tissue microarrays have been constructed, sectioned, and stained by H&E and immunohistochemistry for 229 patients with DLBCL diagnosed 2008-2017. For CD56 positive cases, clinical data was collected including age at diagnosis, stage of the disease, International Prognostic Index (IPI) score, treatment scheme and number of chemotherapy cycles, radiation therapy, treatment outcome, and possible relapse of the disease. Overall survival (OS) and progression-free survival (PFS) were calculated. For four patients, RNA was extracted and targeted RNA (cDNA) sequencing of 125 genes was performed with the Archer FusionPlex Lymphoma kit. RESULTS: CD56 expression was found in 7 cases (3%). The intensity of expression varied from weak to moderate focal, to very intensive and diffuse. All patients had de novo DLBCL. The median age at the time of diagnosis was 54.5 years. Five of them were women and 2 males. According to the Hans algorithm, 6 patients had the germinal centre B cells (GBC) type and one non-GBC (activated B-cell [ABC]) type, double expressor. Genetic profiling of four patients according to Schmitz's classification showed that 1 case was of the BN2 subtype, 1 of EZB subtype, 2 were unclassified. The six treated patients reached a complete response and did not experience progression of the disease during the median follow-up period of 80.5 months. CONCLUSIONS: We report on one of the largest series of CD56+DLBCL with detailed clinicopathological data and for the first time described genetical findings in a limited number of patients. Our results show that CD56 expression is rare, but seems to be present in prognostic favourable subtypes of DLBCL not otherwise specified (NOS) as tested by immunohistochemical or genetic profiling.

Treatment outcomes and relative dose intensity of chemotherapy in patients with advanced Hodgkin lymphoma.

The present retrospective study was undertaken to investigate the association of relative dose intensity (RDI) with the outcome of patients with advanced stage Hodgkin lymphoma (HL) receiving ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) and escalated BEACOPP regimens (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone). A total of 114 patients with HL treated between 2004 and 2013 were enrolled for evaluation. The association of variables with overall survival (OS) and progression-free survival (PFS) was analysed using univariate and multivariate Cox proportional hazards models. The median age of patients was 39 years, and the majority were male and had stage IV disease. A total of 54 patients received ABVD and 60 received BEACOPP chemotherapy with 24 and four deaths, respectively. Patients in the BEACOPP group were significantly younger with lower Charlson comorbidity index (CCI) and better performance status in comparison with the ABVD group, making the comparison of groups not possible. In the ABVD group, RDI was not significantly associated with OS (P=0.590) or PFS (P=0.354) in a multivariate model where age was controlled. The low number of events prevented this analysis in the BEACOPP group. The age of patients was strongly associated with both OS and PFS; all statistically significant predictors for OS and PFS from univariate analyses (chemotherapy regimen, CCI, RDI, performance status) lost their effect in multivariate analyses where age was controlled. Based on these observations, it was concluded that RDI was not associated with OS or PFS after age is controlled, neither in all patients combined nor in the ABVD group.

Correlation of treatment outcome in sanger/RT­qPCR KIT/PDGFRA wild­type metastatic gastrointestinal stromal tumors with next­generation sequencing results: A single­center report.

In patients with gastrointestinal stromal tumors (GIST), it has become mandatory to determine the driver mutation in order to predict the response to standard treatment with tyrosine kinase inhibitors (TKI). A total of 10­15% of all GIST lack activating mutations in KIT proto­oncogene, receptor tyrosine kinase (KIT)/platelet­derived growth factor receptor alpha (PDGFRA) and have been classified as KIT/PDGFRA wild­type (WT) GIST. They are characterized by poor response to TKI. From a group of 119 metastatic GIST patients, 17 patients with KIT/PDGFRA/BRAF WT GIST as determined by reverse transcription­quantitative (RT­q) PCR and Sanger sequencing were profiled by a targeted next­generation sequencing (NGS) approach and their treatment outcome was assessed. In the present study, 41.2% of patients as KIT/PDGFRA/BRAF WT GIST examined with RT­qPCR and Sanger sequencing were confirmed to be carriers of pathogenic KIT/PDGFRA mutations by NGS and were responsive to TKI. The percentage of genuinely KIT/PDGFRA WT GIST in the present study thereby dropped from the initial 14.3% detected with the RT­qPCR and Sanger sequencing to 7.6% after NGS. Their outcome was universally poor. The reliability of RT­qPCR and direct Sanger sequencing results in this setting is therefore insufficient and it is recommended that NGS becomes a requirement for treatment decision at least in KIT/PDGFRA/BRAF WT GIST as determined by RT­qPCR and Sanger sequencing.

Current Opinion on Pixantrone in the Treatment of Non-Hodgkin B-Cell Lymphoma.

Not many treatment options exist for patients with relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) in whom first- and second-line therapies were unsuccessful. This is especially true for patients with aggressive lymphomas. The innovative agent pixantrone has shown some promising results in terms of disease-free and overall survival, both in monotherapy as well as in combinations. However, recent trials (Phase III and real-world studies) reported unsatisfactory results, thereby raising the question about the role of pixantrone in the current treatment of R/R aggressive lymphomas. Nonetheless, there might still be a potential position for this drug in combinations, for use as first-line treatment of patients with cardiac dysfunction. This article summarizes the definition, structure, mechanism of action and reduced cardiotoxicity of pixantrone as well as efficacy and toxicity both in monotherapy and in combinations, as treatment for aggressive and indolent non-Hodgkin lymphomas.

Diffuse large B-cell lymphoma: 10 years' real-world clinical experience with rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisolone.

Treatment with rituximab plus a regimen of cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) for patients with diffuse large B-cell lymphoma (DLBCL) has proven efficacy in clinical trials. The present study investigated its application in clinical practice. This single-center, retrospective database analysis included patients with DLBCL treated at the Slovenian Institute of Oncology Ljubljana between 2004 and 2013. Overall survival (OS) and progression-free survival (PFS) were assessed according to International Prognostic Index (IPI) and revised IPI (R-IPI) categories. Overall, 573 patients with DLBCL were included in the study (median follow-up, 45.3 months; range, 0.1-143.0). Patients were categorized as IPI 'low' (n=170; 30%), 'low-intermediate' (n=134; 23%), 'high-intermediate' (n=129; 23%) and 'high' (n=140; 24%) risk. R-IPI groups were indicated with 'very good' (n=59; 10%), 'good' (n=245; 43%) and 'poor' (n=269; 47%) prognosis. Ten-year OS and PFS rates were 51 and 72%, respectively; median OS was 124 months and median PFS was not reached. Ten-year OS rates were 80 and 87% in low-risk and 'very good' prognosis groups, respectively, and 30 and 37% in high-risk and poor prognosis patients, respectively. This analysis of patients with DLBCL indicated that many patients treated with R-CHOP and R-CHOP-like regimens in the real-world setting have excellent outcomes.

Population pharmacokinetics of rituximab in patients with diffuse large B-cell lymphoma and association with clinical outcome.

AIMS: Pharmacokinetic (PK) studies suggest that there is a room for improvement in clinical use of rituximab through more individualized treatment. The objective of this study was to characterize rituximab PK in 29 newly diagnosed patients with diffuse large B-cell lymphoma treated with rituximab in combination with cyclophosphamide, doxorubicin, vincristine and methylprednisolone every 3 weeks. We also evaluated the association of rituximab PK with clinical outcome. METHODS: Rituximab serum levels were determined by enzyme-linked immunosorbent assay and evaluated by a population PK analysis applying nonlinear mixed effects modelling. RESULTS: The data were best described by a two-compartment model comprising linear nonspecific clearance of 0.252 [95% confidence interval (CI): 0.227-0.279] l day-1 and time-varying specific clearance of 0.278 (95% CI: 0.181-0.390) l day-1 , corresponding to target-mediated drug disposition of rituximab. Nonspecific clearance was lower in older patients and those with lower body weight. Additionally, volume of the central compartment was higher in males. A clear association of clinical response with rituximab PK has been observed. Rate constant of specific clearance decay was 0.143 day-1 (95% CI: 0.0478-0.418) in patients with no disease progression, while in patients with disease progression it was 82.2% lower (95% CI: 33.4-95.0). CONCLUSIONS: This finding indicates that time-changes in clearance could serve as a predictive marker of response to rituximab. Our report demonstrates the rationale for studies evaluating higher doses of rituximab in selected patients.

Fertility in young patients following treatment for Hodgkin's lymphoma: a single center survey.

PURPOSE: The purpose of this study was to determine the fertility rates following treatment by means of the BEACOPP regimen (regular and escalated) (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone) as compared to the ABVD regimen (doxorubicin, vinblastine, dacarbazine, bleomycin) in Hodgkin lymphoma patients under the age of 40 at the time of treatment. METHODS: A questionnaire was sent to 180 Hodgkin lymphoma (HL) patients. The questionnaire was composed of questions concerning reproduction and also menopausal and aging symptoms in females and males. The analyses were made using data collected from 123 patients (76 females and 47 males) who returned the questionnaire. All of the patients were treated between 1999 and 2012. RESULTS: In comparing the ABVD and BEACOPP groups of female patients, the frequency of the therapy-induced amenorrhea and the restored menses following treatment were found to be significantly different statistically (p = 0.002 and p = 0.012, respectively). The secondary amenorrhea statistically appeared more often in the BEACOPP group (p = 0.003) while the cases of achieving pregnancy and having children after chemotherapy were not significantly different (p = 0.630, p = 0.070, respectively). In comparing the ABVD and BEACOPP treatments in male patients, the only significant difference was in the number of artificially inseminated or in vitro pregnancies achieved in the BEACOPP and escalated BEACOPP group, p = 0.008 and p = 0.002, respectively. In total, 45.2% of patients in the ABVD female group, 34.6% in the BEACOPP female group, 52.6% in the ABVD male group, and 33.3% in the male BEACOPP group, respectively, of patients attempting conception post-therapy, had children after chemotherapy. CONCLUSIONS: Based on these high rates of childbirth following BEACOPP chemotherapy, we have concluded that intensified chemotherapy is not a definite predictor of reduced fertility in young HL patients.

Checkpoint inhibitors in Hodgkin's lymphoma.

Hodgkin's lymphoma is unusual among cancers in that it consists of a small number of malignant Hodgkin/Reed-Sternberg cells in a sea of immune system cells, including T cells. Most of these T cells are reversibly inactivated in different ways and their reactivation may induce a very strong immune response to cancer cells. One way of reactivation of T cells is with antibodies blocking the CTLA-4 and especially with antibodies directed against PD-1 or the PD-L1 ligand thereby reversing the tumor-induced downregulation of T-cell function and augmenting antitumor immune activity at the priming (CTLA-4) or tissue effector (PD-1) phase. Immune checkpoint inhibitors have been evidenced as an additional treatment option with substantial effectiveness and acceptable toxicity in heavily pretreated patients with Hodgkin's lymphoma. Particularly, PD-1 blockade with nivolumab and pembrolizumab has demonstrated significant single-agent activity in this select population.

Outcomes of Treatment in Slovene Follicular Lymphoma Patients.

BACKGROUND: The outcome of follicular lymphoma (FL) patients has dramatically improved over the last 2 decades by introduction of rituximab in combination chemotherapy and into maintenance setting. We retrospectively analyzed the treatment outcomes in Slovene FL patients in the era of rituximab and compared them to the results reported by pivotal clinical studies. PATIENTS AND METHODS: Two hundred seventy-eight patients with FL treated in Slovenia between 2000 and 2010 with a median follow-up of 5.7 years were included in our retrospective analysis. One hundred ninety-three (69%) received systemic treatment (ST). RESULTS: With a median follow-up of 5.7 years, the 5- and 10-year overall survival (OS) rates for the whole series were 77% and 53%, respectively. The 5-year progression-free survival (PFS) for 193 FL patients treated with ST was 37%. Patients treated with rituximab chemotherapy had a significantly better OS than patients treated with chemotherapy alone, with a 5-year OS of 79% versus 53% (hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.22-0.67; P = .001). Adding rituximab to the first-line chemotherapy significantly improved PFS compared to chemotherapy alone (HR, 0.26; 95% CI 0.18-0.36; P < .001). Maintenance rituximab after immunochemotherapy in first-line treatment reduced the risk for progression by 61% and significantly prolonged the time to progression (HR, 0.39; 95% CI 0.20-0.73; P < .003). CONCLUSION: The outcomes in our routinely treated FL patients confirm the benefit of adding rituximab to chemotherapy and are comparable to the results of pivotal clinical studies. The outcome of our FL patients was improved in terms of both PFS and OS.

Urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) in breast cancer - correlation with traditional prognostic factors.

BACKGROUND: Urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) play a key role in tumour invasion and metastasis. High levels of both proteolytic enzymes are associated with poor prognosis in breast cancer patients. The purpose of this study was to evaluate the correlation between traditional prognostic factors and uPA and PAI-1 expression in primary tumour of breast cancer patients. PATIENTS AND METHODS: 606 primary breast cancer patients were enrolled in the prospective study in the Department of gynaecological oncology and breast oncology at the University Medical Centre Maribor between the years 2004 and 2010. We evaluated the traditional prognostic factors (age, menopausal status, tumour size, pathohistological type, histologic grade, lymph node status, lymphovascular invasion and hormone receptor status), together with uPA and PAI-1. We used Spearman's rank correlation, Mann Whitney U test and χ(2) test for statistical analysis. RESULTS: Our findings indicate a positive correlation between uPA and tumour size (p < 0.001), grade (p < 0.001), histological type (p < 0.001), lymphovascular invasion (p = 0.01) and a negative correlation between uPA and hormone receptor status (p < 0.001). They also indicate a positive correlation between PAI-1 and tumour size (p = 0.004), grade (p < 0.001), pathohistological type (p < 0.001) and negative correlation between PAI-1 and hormone receptor status (p = 0.002). CONCLUSIONS: Our study showed a relationship between uPA and PAI-1 and traditional prognostic factors. Their role as prognostic and predictive factors remains to be further evaluated.

Diagnostic value of immunoglobulin κ light chain gene rearrangement analysis in B-cell lymphomas.

Analysis of the immunoglobulin κ light chain (IGK) gene is an alternative method for B-cell clonality assessment in the diagnosis of mature B-cell proliferations in which the detection of clonal immunoglobulin heavy chain (IGH) gene rearrangements fails. The aim of the present study was to evaluate the added value of standardized BIOMED-2 assay for the detection of clonal IGK gene rearrangements in the diagnostic setting of suspected B-cell lymphomas. With this purpose, 92 specimens from 80 patients with the final diagnosis of mature B-cell lymphoma (37 specimens), mature T-cell lymphoma (26 specimens) and reactive lymphoid proliferation (29 specimens) were analyzed for B-cell clonality. B-cell clonality analysis was performed using the BIOMED-2 IGH and IGK gene clonality assays. The determined sensitivity of the IGK assay was 67.6%, while the determined sensitivity of the IGH assay was 75.7%. The sensitivity of combined IGH+IGK assay was 81.1%. The determined specificity of the IGK assay was 96.2% in the group of T-cell lymphomas and 96.6% in the group of reactive lesions. The determined specificity of the IGH assay was 84.6% in the group of lymphomas and 86.2% in the group of reactive lesions. The comparison of GeneScan (GS) and heteroduplex pretreatment-polyacrylamide gel electrophoresis (HD-PAGE) methods for the analysis of IGK gene rearrangements showed a higher efficacy of GS analysis in a series of 27 B-cell lymphomas analyzed by both methods. In the present study, we demonstrated that by applying the combined IGH+IGK clonality assay the overall detection rate of B-cell clonality was increased by 5.4%. Thus, we confirmed the added value of the standardized BIOMED-2 IGK assay for assessment of B-cell clonality in suspected B-cell lymphomas with inconclusive clinical and cyto/histological diagnosis.

The diffuse large B-cell lymphoma - where do we stand now in everyday clinical practice.

BACKGROUND: Due to superior results observed with the addition of rituximab into treatment of patients with the diffuse large B-cell lymphoma (DLBCL),the R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) regimen and its variants became the standard initial treatment of these patients. However, the treatment recommendations are based on results of clinical studies while the conditions of routine treatment are far different from the ones in clinical studies. The aim of this retrospective study was therefore to compare the treatment results of routinely treated patients with the DLBCL to results reported by some larger studies. PATIENTS AND METHODS: Two hundred and ninety five patients with the DLBCL were treated between 2004 and 2008 according to the then protocol with R-CHOP or R-CHOP-like regimens at the Institute of Oncology Ljubljana. Treatment response was evaluated according to Cheson's criteria and the disease-free and overall survival by means of Kaplan Meier survival curves. RESULTS: Response to treatment in our evaluation diverged from the reported one predominately in the low risk group (international prognostic index [IPI] categorisation) and in the very good prognosis group (revised international prognostic index (R-IPI) categorisation). The determined complete response (CR) rates in other IPI and R-IPI groups were generally within expectations. Also in the disease-free survival the largest discrepancy occurred in the low-risk patient group (3 year disease-free survival rate of 75%) and in the very good prognosis group (4 year disease-free survival rate of 59%). In all other IPI risk groups, the disease-free survival at 3 years (low intermediate risk 76%, high intermediate risk group 57%, and high risk group 53%) agreed very well with the quoted ones. Slightly worse was the compliance of the 4 year disease-free survival rates (72% in the good prognosis and 51% in the poor prognosis group) with the results from the literature. The 3 year overall survival rates (low risk patients 87%, high intermediate risk 61% and high risk patients 51%) were somewhat worse than the reported ones in all IPI subgroups except in the low intermediate risk group (82%). On the other hand, the 4 year overall survival rates of the R-IPI categories (94% in the very good prognosis group, 80% in the good prognosis group, 56% in the poor prognosis group) were much better correlated with the data from the literature. CONCLUSIONS: In total, the treatment outcomes of routinely treated patient with the DLBCL at our institute are quite encouraging when compared to results of some larger studies. There are probably no dilemmas about how to treat young good prognosis patients and patients aged over 60 years at present. However, the 5 year overall survival rate of 76% for the young poor prognosis group is unsatisfying and needs to be improved. At present, quite a few studies are underway to clarify which of the regimens will perform best in this population.

Treatment outcomes and survival in patients with primary central nervous system lymphomas treated between 1995 and 2010 - a single centre report.

BACKGROUND.: Primary central nervous system lymphomas (PCNSL) are rare variants of extranodal non-Hodgkin's lymphomas that are nowadays primarily treated with high-dose methotrexate or methotrexate-based chemotherapy with or without radiation therapy. The optimal treatment of PCNSL is still unknown and there are differences in clinical practice. PATIENTS AND METHODS.: With a retrospective research we evaluated our series of patients with PCNSL in regards to the patient's characteristics, treatment results, disease specific survival and overall survival. Fifty nine patients who attended the Institute of Oncology Ljubljana between 1995 and 2010 were treated according to the protocol that was valid at the time of the patient's admission. Between 1995 and 1999, the systemic treatment was classical CHOP (cyclophosphamide, doxorubicin, vincristine, steroids) chemotherapy, and later on high-dose methotrexate either alone or in combination with other agents. From 1999 onwards, radiation therapy was applied according to the patient's age and response to chemotherapy, prior to that all patients treated with CHOP were also irradiated. Patients ineligible for the systemic treatment were treated with sole radiation therapy. RESULTS.: There was a strong female predominance in our series and the median age at diagnosis was 59.8 years. Patients had predominantly aggressive B cell lymphomas (69.5%), one patient had marginal cell lymphoma and two patients T cell lymphoma. In total, 20.3% of patients were treated just with chemotherapy, 33.9% with combined therapy and 42.4% with sole radiation therapy. The overall response rate to the primary treatment in patients treated with sole chemotherapy was 33.3%, in patients treated with combined therapy 65% and in patients treated only with radiation therapy 56%, respectively. In terms of response duration, significantly better results were achieved with combined therapy or radiation therapy alone compared to sole chemotherapy (p<0.0006). The median overall survival of the whole cohort was 11 months and the overall survival was significantly affected by the patient's age. The longest overall survival was observed in patients treated with combined therapy (median survival of 39 months). Patients treated just with radiation therapy had a median overall survival of 9 months and those treated with sole chemotherapy of 4.5 months, respectively. CONCLUSIONS.: The treatment outcomes in ordinary clinical practice are definitely inferior to the ones reported in clinical trials. The now standard treatment with high-dose methotrexate with or without radiation therapy is sometimes too aggressive and, therefore, a careful selection on the basis of patient's age, performance status and concomitant diseases of those eligible for such treatment is mandatory. According to our results from a retrospective study, radiation therapy should not be excluded from the primary treatment.

Tumor vaccine composed of CpG ODN class C and irradiated tumor cells up-regulates the expression of genes characteristic of mature dendritic cells and of memory cells.

Only properly mature dendritic cells (DCs) in the presence of tumor antigens accomplish to activate all of the elements of the immune network and have the potential to induce tumor-specific effectors and memory T cells. In the current study, we firstly aimed to investigate the in vivo maturation of antigen presenting cells (APCs) at the molecular level by following the expression of CD11c, CD86 and MyD88 genes in the mixture of mononuclear cells after treatment of mice with a tumor vaccine composed of C-class CpG oligodeoxynucletides (CpG ODN) and irradiated melanoma B16F1 tumor cells. The second objective was to define whether the tumor vaccine induces generation of memory T cells (CD44hiCD62Llo/hiCD27hi). Finally, based on gene expression pattern we aimed to determine the tissue distribution and homing of the (mature) APCs and memory cells after vaccination. We demonstrated that by tumor vaccine the APCs (including DCs) are manipulated in vivo. By this kind of vaccine, the differentiation and maturation of APCs is triggered primarily in the spleen and is subsequently followed by the migration of these APCs to the bone marrow. Once in the bone marrow, these APCs play a crucial role in the development and maintenance of long-lived memory T cells capable of preventing a relapse of malignant disease. In conclusion, our results provide insight into the nature and scope of the antitumor immune response elicited by this kind of tumor vaccine in vivo. We showed that the maturation of APCs is a prerequisite for the generation of effective long-term antitumor immunity.

Predictive significance of the cut-off value of CD20 expression in patients with B-cell lymphoma.

The introduction of the anti-CD20 monoclonal antibody, rituximab, into the treatment of patients with B-cell lymphomas has improved the overall response rate, as well as the response duration and the overall survival of these patients. However, only a few studies have addressed the question of whether higher CD20 expression parallels with better treatment outcomes. The aim of this study was to assess the relationship between the level of CD20 expression and overall survival (OS), disease-free survival (DFS) along with the overall response rate (ORR) in B-cell lymphoma patients. The ultimate objective of the study was to determine the cut-off value of CD20 expression together with the predictive significance of better outcome of rituximab treatment. One hundred and fourteen patients with different histological types of B-cell lymphomas treated with rituximab and chemotherapy between 2003 and 2007 were enrolled in the study. All patients had CD20 expression assessed prior to the beginning of treatment. The level of CD20 expression was determined by quantitative flow cytometric measurements, while the OS and DFS were evaluated by means of Kaplan-Meier survival curves. The cut-off value of CD20 expression, which predicts a better response to rituximab in patients with B-cell lymphomas, was determined at 25.000 molecules of equivalent soluble fluorochrome (MESF). Our data show that patients who achieved complete response after rituximab therapy had a significantly higher expression of the CD20 antigen (p=0.018) than those whose disease only stabilized after rituximab therapy. No significant difference was observed in the response duration between the patients with CD20 antigen expressed above the cut-off value and those expressing CD20 antigen below the cut-off value [hazard ratio (HR), 0.5667; 95%CI, 0.124 to 3.18, p=0.57]. Even though we have proved that patients with a CD20 expression level above the cut-off value treated with rituximab had a significantly longer OS [hazard ratio (HR), 0.4573; 95%CI, 0.1364 to 0.9461, p=0.0383] than patients with a CD20 expression level below the cut-off value. Among our study population, 17.5% had a CD20 expression level below the cut-off value. The highest percentage (80%) of the patients with a CD20 expression level below the cut-off value belonged to the group of chronic lymphocytic leukemia (CLL) patients, while the lowest (6.7%) was observed in the follicular lymphoma (FL) patient group. These data indicate that a higher level of CD20 expression correlates with an improved OS in patients treated with rituximab. The cut-off limit of CD20 expression suggested to have the predictive significance of better outcome was in our series set at 25.000 MESF. This cut-off value should be considered when the decision regarding treatment with rituximab is taken. However, these results warrant further studies on larger groups of patients.

Treatment of non-Hodgkin's lymphomas with rituximab in Slovene patients.

The introduction of rituximab into the treatment of patients with NonHodgkin's lymphomas has changed the long-term prognosis of patients with CD20 positive B cell lymphomas, especially follicular and diffuse large B-cell lymphomas (DLBCLs). The addition of rituximab to chemotherapy improves the overall response rate, prolongs the response duration and the overall survival both in patients with follicular and other indolent CD20 positive lymphomas, and DLBCLs. Maintenance treatment with rituximab in patients with indolent lymphomas further prolongs the remission duration, and some of the studies have also shown survival benefit. However, the maintenance therapy in aggressive lymphomas most probably gives no further improvement in patients, who have received rituximab already in the induction treatment. Rituximab has been used at the Institute of Oncology Ljubljana since 1998. In the period from 2004 to 2006, we have treated 340 patients with rituximab either as a single agent or in combination with chemotherapy. Our treatment group included 46.8% of patients with DLBCLs and 19.4% with follicular lymphomas. In majority of the patients, rituximab was given as the first-line treatment (54.4%), while 26.2% of patients received it as the second-line treatment and 19.4% of patients as the third or subsequent line of treatment. Among patients with indolent lymphomas, just 15% received rituximab as the first-line treatment. On the other hand, 75.9% of patients with aggressive lymphomas were treated with rituximab for newly diagnosed disease. About 67.4% of patients were treated with R-CHOP combination, while the others received different rituximab-chemotherapy combinations. The overall response rate regardless of the histological type of lymphoma was 78.8%, and the highest response rate was achieved in patients with aggressive follicular lymphomas (91.7%). The highest overall response rate was observed when rituximab was given as the first-line treatment in all lymphoma types except the mantle cell lymphoma (66.6% overall response rate for the first-line treatment versus 73.7% overall response rate for the second-line treatment). In 75% of patients regardless of the histological type of lymphoma, the response lasted more than 12 months; the median response duration has not been reached yet. In patients receiving rituximab as the first-line treatment, the median response duration also has not been reached yet, while for the second-line treatment, it was 25 months and for the third or subsequent line, 24 months. The longest disease-free survival was observed in patients with DLBCLs. The overall survival rate of all patients regardless of the type of lymphoma was 75% 26 months after the beginning of the treatment, and the median overall survival has not been reached yet. When analyzed by the lines of treatment-the median overall survival has not been reached in any line. The longest overall survival was observed in patients with indolent follicular lymphomas. The treatment results with rituximab at the Institute of Oncology Ljubljana are comparable to the results of larger randomized trials. According to the beneficial influence of rituximab on the long-term prognosis of patients with CD20 positive lymphomas, it became the standard of treatment in these patients.

Class C CpG oligodeoxynucleotides as a single agent and in combination with radiotherapy efficiently delayed growth of subcutaneous B16F1 tumors.

Until now, the anti-tumor efficacy of synthetic oligodeoxynucleotides containing CpG motifs (CpG ODNs) has been reported in a number of preventive and therapeutic tumor models. Predominately class B CpG ODNs were used, relatively little has been reported regarding the class C CpG ODNs. The present study was, therefore, aimed at assessing the ability of CpG ODNs class C applied as a single agent and in combination with radiotherapy to induce the anti-tumor immunity in an experimental tumor model in mice (subcutaneous [s.c.] B16F1). Class C CpG ODNs applied three times as a single agent efficiently delayed the growth of s.c. B16F1 tumors. The combined therapy (CpG ODNs and tumor irradiation) remarkably enhanced the anti-tumor effect. The peritumoral (p.t.) application of CpG ODNs in combination with irradiation increased the number of dendritic cells (DCs) at the tumor site and improved the antigen loading and maturation of DCs. In conclusion, the combined therapy with CpG ODNs and irradiation creates a unique in situ DCs vaccine that could be easily applicable without prior knowledge of tumor antigens.