Exposure to obinutuzumab does not affect outcomes of SARS-CoV-2 infection in vaccinated patients with newly diagnosed advanced-stage follicular lymphoma.

URBAN is a multicentric, ambispective study evaluating the effectiveness and safety of obinutuzumab-based immuno-chemotherapy and maintenance in patients with untreated advanced follicular lymphoma (FL). The study began before the COVID-19 emergency declaration in Italy. It is currently ongoing for follow-up, and the enrolment timeline encompassed different stages of the pandemic, various vaccination roll-out phases and prevalence of SARS-CoV-2 variants. Outcomes of interest of the present sub-analysis included SARS-CoV-2 infection rates and COVID-19-related hospitalizations/deaths. At data cut-off, 86 (28.8%) and 213 patients (71.2%) were treated before and during/after the COVID-19 outbreak respectively; 294 (98.3%) completed the induction, 31 (10.4%) completed maintenance and 170 (56.9%) were still on maintenance. Overall, 245 patients (81.9%) received at least one SARS-CoV-2 vaccine dose: 13.5%, 31.4% and 55.1% received one, two and three doses respectively. We observed a substantial decrease in COVID-19-related mortality rates in pre- versus post-vaccination phases, along with a reduction in COVID-19-related outcomes due to the shift from alpha/delta to omicron variant predominance. No differences emerged between patients given maintenance or not, although the schedule was modified in 65% of cases. To our knowledge, URBAN represents the largest dataset of COVID-19-related outcomes in FL patients extensively exposed to obinutuzumab. ClinicalTrials.gov identifier: NCT04034056.

Radioimmunotherapy versus autologous hematopoietic stem cell transplantation in relapsed/refractory follicular lymphoma: a Fondazione Italiana Linfomi multicenter, randomized, phase III trial.

BACKGROUND: Optimal consolidation for young patilents with relapsed/refractory (R/R) follicular lymphoma (FL) remains uncertain in the rituximab era, with an unclear benefit of autologous stem cell transplantation (ASCT). The multicenter, randomized, phase III FLAZ12 (NCT01827605) trial compared anti-CD20 radioimmunotherapy (RIT) with ASCT as consolidation after chemoimmunotherapy, both followed by rituximab maintenance. PATIENTS AND METHODS: Patients (age 18-65 years) with R/R FL and without significant comorbidities were enrolled and treated with three courses of conventional, investigator-chosen chemoimmunotherapies. Those experiencing at least a partial response were randomized 1 : 1 to ASCT or RIT before CD34+ collection, and all received postconsolidation rituximab maintenance. Progression-free survival (PFS) was the primary endpoint. The target sample size was 210 (105/group). RESULTS: Between August 2012 and September 2019, of 164 screened patients, 159 were enrolled [median age 57 (interquartile range 49-62) years, 55% male, 57% stage IV, 20% bulky disease]. The study was closed prematurely because of low accrual. Data were analyzed on 8 June 2023, on an intention-to-treat basis, with a 77-month median follow-up from enrollment. Of the 141 patients (89%), 70 were randomized to ASCT and 71 to RIT. The estimated 3-year PFS in both groups was 62% (hazard ratio 1.11, 95% confidence interval 0.69-1.80, P = 0.6662). The 3-year overall survival also was similar between the two groups. Rates of grade ≥3 hematological toxicity were 94% with ASCT versus 46% with RIT (P < 0.001), and grade ≥3 neutropenia occurred in 94% versus 41%, respectively (P < 0.001). Second cancers occurred in nine patients after ASCT and three after radioimmunotherapy (P = 0.189). CONCLUSIONS: Even if prematurely discontinued, our study did not demonstrate the superiority of ASCT versus RIT. ASCT was more toxic and demanding for patients and health services. Both strategies yielded similar, favorable long-term outcomes, suggesting that consolidation programs milder than ASCT require further investigation in R/R FL.

Quantitative muscle mass biomarkers are independent prognosis factors in primary central nervous system lymphoma: The role of L3-skeletal muscle index and temporal muscle thickness.

OBJECTIVE: To investigate the role of quantitative muscle biomarkers assessed with skeletal muscle index at the third lumbar vertebra (L3-SMI) and temporal muscle thickness (TMT) in predicting progression-free and overall survival in patients with primary central nervous system lymphoma (PCNSL) undergoing first-line high-dose methotrexate-based chemotherapy. METHODS: L3-SMI and TMT were calculated on abdominal CT and brain high-resolution 3D-T1-weighted MR images, respectively, using predefined validated methods. Standardized sex-specific cut-off values were used to divide patients in different risk categories. Kaplan-Meier plots were calculated, and survival analysis was performed using log-rank tests, univariate, and multivariable Cox-regression models, calculating hazard ratios (HR) and 95% confidence intervals (CI), also adjusting for potential confounders (age, sex, and performance status). RESULTS: Forty-three patients were included in this study. Median follow-up was 23 months (interquartile range 12-40); at median follow-up, rates of progression-free and overall survival for the cohort were 46% and 57%, respectively. Thirteen (30%) and 11 (26%) patients showed L3-SMI or TMT values below the predefined cut-offs. In Cox-regression multivariable analysis patients with low L3-SMI or TMT showed significantly worse progression-free (HR 4.40, 95% CI 1.66-11.61, p = 0.003; HR 4.40, 95% CI 1.68-11.49, p = 0.003, respectively) and overall survival (HR 3.16, 95% CI 1.09-9.11, p = 0.034; HR 4.93, 95% CI 1.78-13.65, p = 0.002, respectively) compared to patients with high L3-SMI or TMT. CONCLUSIONS: Quantitative muscle mass evaluation assessed by both L3-SMI and TMT is a promising tool to identify PCNSL patients at high risk of negative outcome. Confirmatory studies on larger independent series are warranted.

How we treat primary central nervous system lymphoma.

Primary diffuse large B-cell (DLBCL) lymphoma of the central nervous system (CNS) (PCNSL) is a new lymphoma entity, recognized by the 2017 WHO classification of hematopoietic and lymphoid tumors. Unlike systemic DLBCL, the use of anthracycline-based chemotherapy combinations is associated with disappointing outcomes, due to low CNS bioavailability of related drugs. Therefore, international researchers investigated alternative strategies, mostly including drugs able to cross the blood-brain-barrier at low or high doses, with a progressive improvement in survival. Some effective chemotherapy combinations of high-dose methotrexate (HD-MTX) with alkylating agents and rituximab with or without cytarabine have been tested in international randomized trials and represent the induction treatment in everyday practice, with some variations among different geographical areas. In patients aged 70 years or younger, MATRix (HD-MTX/cytarabine/thiotepa/rituximab) chemotherapy followed by consolidative high-dose chemotherapy plus autologous stem cell transplantation or whole-brain irradiation has been associated with a significant improvement in overall survival. Other treatment options, such as non-myeloablative high-dose chemotherapy, oral drug maintenance, and some targeted drugs like ibrutinib or lenalidomide, are being tested in high-level international trials. These steps toward further effective treatments are motivated by an incessant search for less neurotoxic options. Thanks to international cooperation, we can affirm that PCNSL is a potentially curable tumor, especially in young patients. However, several questions remain unanswered: the optimal treatment for elderly patients as well as the management of intraocular and meningeal disease require further scientific efforts. Beside treatments, advances on molecular and radiological diagnostic tools will increase our knowledge of this disease, allowing the possibility to anticipate diagnosis and to better categorize patients' responses. This article analyzes the available literature in this setting and provides evidence-based recommendations for the management of PCNSL patients.

ESMO Consensus Conference on malignant lymphoma: management of 'ultra-high-risk' patients.

The European Society for Medical Oncology (ESMO) consensus conference on malignant lymphoma was held on 20 June 2015 in Lugano, Switzerland, and included a multidisciplinary panel of 25 leading experts. The aim of the conference was to develop recommendations on critical subjects difficult to consider in detail in the ESMO Clinical Practice Guidelines. The following areas were identified: (1) the elderly patient, (2) prognostic factors suitable for clinical use and (3) the 'ultra-high-risk' group. Before the conference, the expert panel was divided into three working groups; each group focused on one of these areas in order to address clinically relevant questions relating to that topic. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, each working group developed recommendations to address each of the questions devised by their group. These recommendations were then presented to the entire multidisciplinary panel and a consensus was reached. This manuscript presents recommendations regarding the management of the following 'ultra-high-risk' situations: (1) early central nervous system relapse of diffuse large B-cell lymphoma, (2) primary refractory Hodgkin lymphoma and (3) plasmablastic lymphoma. Results, including a summary of evidence supporting each recommendation, are detailed in this manuscript. All expert panel members approved this final article.

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.

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.

High-dose clarithromycin is an active monotherapy for patients with relapsed/refractory extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT): the HD-K phase II trial.

BACKGROUND: Clarithromycin displays immunomodulatory and antineoplastic properties. As single agent, this macrolide is associated with tumor responses in anecdotal cases of relapsed/refractory extranodal marginal zone lymphoma (rrEMZL), with a putative dose-dependent effect. Tolerability and activity of high-dose clarithromycin (HD-K) in patients with rrEMZL were addressed in a phase II trial (clinicaltrials.gov NCT01516606). METHODS: HIV-negative adults with rrEMZL and at least one measurable/parametrable lesion were enrolled and treated with four courses of oral clarithromycin 2 g/day, days 1-14, every 21 days. Activity (overall response rate, ORR) was the primary end point. RESULTS: Twenty-three patients were registered (median age 70 years, range 47-88 years; M:F ratio: 0.27). HD-K was given at greater than or equal to second relapse in 11 patients. Ocular adnexae were the most commonly involved organs. Five patients had hepatitis B virus/hepatitis C virus (HBV/HCV) infections; Helicobacter pylori and Chlamydophila psittaci infections were excluded at the time of patient registration.Tolerability was excellent, even among HBV/HCV-positive patients; only two patients had grade >2 toxicity (nausea). Six patients achieved a complete remission and six a partial response (ORR = 52%; 95% confidence interval 32% to 72%). Age, previous treatment and stage did not influence activity. At a median follow-up of 24 (16-33) months, only two patients with responsive disease experienced relapse, with a 2-year progression-free survival of 56 ± 10%; all patients are alive. CONCLUSIONS: HD-K is a safe and active salvage treatment in EMZL patients. This macrolide deserves to be further investigated in EMZL and other lymphoma categories.

First-line treatment and outcome of elderly patients with primary central nervous system lymphoma (PCNSL)--a systematic review and individual patient data meta-analysis.

BACKGROUND: To investigate prognosis and effects of first-line therapy in elderly primary central nervous system lymphoma (PCNSL) patients. PATIENTS AND METHODS: A systematic review of studies about first-line therapy in immunocompetent patients ≥60 years with PCNSL until 2014 and a meta-analysis of individual patient data from eligible studies and international collaborators were carried out. RESULTS: We identified 20 eligible studies; from 13 studies, we obtained individual data of 405 patients, which were pooled with data of 378 additional patients (N = 783). Median age and Karnofsky Performance Score (KPS) was 68 years (range: 60-90 years) and 60% (range: 10%-100%), respectively. Treatments varied greatly, 573 (73%) patients received high-dose methotrexate (HD-MTX)-based therapy. A total of 276 patients received whole-brain radiotherapy (median 36 Gy, range 28.5-70 Gy). KPS ≥ 70% was the strongest prognostic factor for mortality [hazard ratio (HR) 0.50, 95% confidence interval (CI) 0.41-0.62]. After a median follow-up of 40 months, HD-MTX-based therapy was associated with improved survival (HR 0.70, 95% CI 0.53-0.93). There was no difference between HD-MTX plus oral chemotherapy and more aggressive HD-MTX-based therapies (HR 1.39, 95% CI 0.90-2.15). Radiotherapy was associated with an improved survival, but correlated with an increased risk for neurological side-effects (odds ratio 5.23, 95% CI 2.33-11.74). CONCLUSIONS: Elderly PCNSL patients benefit from HD-MTX-based therapy, especially if combined with oral alkylating agents. More aggressive HD-MTX protocols do not seem to improve outcome. WBRT may improve outcome, but is associated with increased risk for neurological side-effects. Prospective trials for elderly PCNSL patients are warranted.

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.

The prognostic role of post-induction FDG-PET in patients with follicular lymphoma: a subset analysis from the FOLL05 trial of the Fondazione Italiana Linfomi (FIL).

BACKGROUND: [18F]fluorodeoxyglucose-positron emission tomography (PET) is emerging as a strong diagnostic and prognostic tool in follicular lymphoma (FL) patients. PATIENTS AND METHODS: In a subset analysis of the FOLL05 trial (NCT00774826), we investigated the prognostic role of post-induction PET (PI-PET) scan. Patients were eligible to this study if they had a PI-PET scan carried out within 3 months from the end of induction immunochemotherapy. Progression-free survival (PFS) was the primary study end point. RESULTS: A total of 202 patients were eligible and analysed for this study. The median age was 55 years (range 33-75). Overall, PI-PET was defined as positive in 49 (24%) patients. Conventional response assessment with CT scan was substantially modified by PET: 15% (22/145) of patients considered as having a complete response (CR) after CT were considered as having partial response (PR) after PI-PET and 53% (30/57) patients considered as having a PR after CT were considered as a CR after PI-PET. With a median follow-up of 34 months, the 3-year PFS was 66% and 35%, respectively, for patients with negative and positive PI-PET (P<0.001). At multivariate analysis, PI-PET (hazard ratio 2.57, 95% confidence interval 1.52-4.34, P<0.001) was independent of conventional response, FLIPI and treatment arm. Also, the prognostic role of PI-PET was maintained within each FLIPI risk group. CONCLUSIONS: In FL patients, PI-PET substantially modifies response assessment and is strongly predictive for the risk of progression. PET should be considered in further updates of response criteria.

The clinical features, management and prognostic effects of pathological fractures in a multicenter series of 373 patients with diffuse large B-cell lymphoma of the bone.

BACKGROUND: Pathological fractures (PFs) occur in 10%-20% of patients with diffuse large B-cell lymphoma (DLBCL) of the bone. The clinical features and the effects of this severe complication on management and prognosis have not been previously analyzed in a large series. PATIENTS AND METHODS: The effects of PF on management and prognosis were reviewed in an international retrospective series of 373 patients with newly diagnosed bone DLBCL, comparing 78 patients with PF at presentation (group 'PF-BL') and 295 patients without PF ('controls'). RESULTS: At a median follow-up of 53 months (range 3-246), PF-BL patients exhibited lower rates of overall response (ORR, 78% versus 85%; P = 0.17), 5-year progression-free survival (PFS, 53 ± 6% versus 61 ± 3%; P = 0.02) and 5-year overall survival (OS, 54 ± 6% versus 68 ± 3%, P = 0.008) than controls. Initial surgical stabilization of the PF did not change therapeutic outcome (5-year OS: 45 ± 9% versus 54 ± 10%; P = 0.20). PF-BL patients referred to irradiation of the fractured bone before chemotherapy exhibited a significantly poorer outcome than patients managed with the inverse sequence (ORR: 52% versus 92%, P = 0.0005; 5-year OS: 22 ± 14% versus 64 ± 9%, P = 0.007). Multivariate analysis confirmed the independent association between PF and worse survival and the negative effect of radiotherapy as initial therapy. CONCLUSION: Fracture is an independent, adverse prognostic event in patients with bone DLBCL. Anthracycline-based chemotherapy followed by radiotherapy seems to be the better treatment sequence. Initial fracture stabilization does not seem to improve outcome; it should be used to improve patient's quality of life only if chemotherapy delays can be avoided.

The use of FDG-PET in the initial staging of 142 patients with follicular lymphoma: a retrospective study from the FOLL05 randomized trial of the Fondazione Italiana Linfomi.

BACKGROUND: The role of [¹8F] fluorodeoxyglucose (FDG)-positron emission tomography (PET) in follicular lymphoma (FL) staging is not yet determined. PATIENTS AND METHODS: The aim of the present study was to investigate the role of PET in the initial staging of FL patients enrolled in the FOLL05-phase-III trial that compared first-line regimens (R-CVP, R-CHOP and R-FM). Patients should have undergone conventional staging and have available PET baseline to be included. RESULTS: A total of 142 patients were analysed. PET identified a higher number of nodal areas in 32% (46 of 142) of patients and more extranodal (EN) sites than computed tomography (CT) scan. Also, the Follicular Lymphoma International Prognostic Index (FLIPI) score increased in 18% (26 of 142) and decreased in 6% (9 of 142) of patients. Overall, the impact of PET on modifying the stage was highest in patients with limited stage. Actually, 62% (15 of 24) of cases with limited disease were upstaged with PET. CONCLUSIONS: The inclusion of PET among staging procedures makes the evaluation of patients with FL more accurate and has the potential to modify therapy decision and prognosis in a moderate proportion of patients. Further prospective clinical trials on FL should incorporate PET at different moments, and the therapeutic criteria to start therapy should be re-visited in the views of this new tool.

Rational administration schedule for high-dose methotrexate in patients with primary central nervous system lymphoma.

Methotrexate (MTX) at a dose of ≥1 g/m(2) remains the most efficient treatment against primary central nervous system lymphoma (PCNSL), and is the most widely used drug in prospective clinical trials. MTX is a folate analog that inhibits dihydrofolate reductase, thereby blocking de novo purine synthesis. MTX as well as 7-hydroxy-MTX, its main metabolite in serum, are both eliminated by the kidneys. The elimination of MTX is prolonged in patients with renal impairment and third-space fluid collections, and in patients receiving concurrent non-steroidal antirheumatic drugs, benzimidazoles and sulfonamides, among others. Main adverse events with high-dose MTX include severe myelosuppression, renal dysfunction and stomatitis. Supportive measures such as rigorous hydration, urine alkalinization and careful drug monitoring with supplemental leucovorin rescue are crucial to avoid significant toxicity. Strategies to optimize clinical efficacy of high-dose MTX in patients with PCNSL include administration of 3 h instead of longer infusions, potentially supplemented with an additional intravenous MTX bolus, and maintaining MTX dose intensity over the course of four treatment cycles. Some pharmacological studies suggest that achieving an MTX area under the plasma concentration-time curve (AUC(MTX)) of between 1000 and 1100 µmol.h/L may improve clinical outcome, but clinical data are not conclusive at present. In this review, we analyze the impact of patient, lymphoma and pharmacokinetic variables on the antitumor activity of high-dose MTX in patients with PCNSL, summarize recommendations for daily clinical practice and give some suggestions for future trials.

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.