Graham W. Slack

Concurrent expression of MYC and BCL2 in diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone

PURPOSE Diffuse large B-cell lymphoma (DLBCL) is curable in 60% of patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). MYC translocations, with or without BCL2 translocations, have been associated with inferior survival in DLBCL. We investigated whether expression of MYC protein, with or without BCL2 protein expression, could risk-stratify patients at diagnosis. PATIENTS AND METHODS We determined the correlation between presence of MYC and BCL2 proteins by immunohistochemistry (IHC) with survival in two independent cohorts of patients with DLBCL treated with R-CHOP. We further determined if MYC protein expression correlated with high MYC mRNA and/or presence of MYC translocation. RESULTS In the training cohort (n = 167), MYC and BCL2 proteins were detected in 29% and 44% of patients, respectively. Concurrent expression (MYC positive/BCL2 positive) was present in 21% of patients. MYC protein correlated with presence of high MYC mRNA and MYC translocation (both P < .001), but the latter was less frequent (both 11%). MYC protein expression was only associated with inferior overall and progression-free survival when BCL2 protein was coexpressed (P < .001). Importantly, the poor prognostic effect of MYC positive/BCL2 positive was validated in an independent cohort of 140 patients with DLBCL and remained significant (P < .05) after adjusting for presence of high-risk features in a multivariable model that included elevated international prognostic index score, activated B-cell molecular subtype, and presence of concurrent MYC and BCL2 translocations. CONCLUSION Assessment of MYC and BCL2 expression by IHC represents a robust, rapid, and inexpensive approach to risk-stratify patients with DLBCL at diagnosis.

Cooperative Epigenetic Modulation by Cancer Amplicon Genes

Chromosome band 9p24 is frequently amplified in primary mediastinal B cell lymphoma (PMBL) and Hodgkin lymphoma (HL). To identify oncogenes in this amplicon, we screened an RNA interference library targeting amplicon genes and thereby identified JAK2 and the histone demethylase JMJD2C as essential genes in these lymphomas. Inhibition of JAK2 and JMJD2C cooperated in killing these lymphomas by decreasing tyrosine 41 phosphorylation and increasing lysine 9 trimethylation of histone H3, promoting heterochromatin formation. MYC, a major target of JAK2-mediated histone phosphorylation, was silenced after JAK2 and JMJD2C inhibition, with a corresponding increase in repressive chromatin. Hence, JAK2 and JMJD2C cooperatively remodel the PMBL and HL epigenome, offering a mechanistic rationale for the development of JAK2 and JMJD2C inhibitors in these diseases.

Genomic rearrangements involving programmed death ligands are recurrent in primary mediastinal large B-cell lymphoma.

The pathogenesis of primary mediastinal large B-cell lymphoma (PMBCL) is incompletely understood. Recently, specific genotypic and phenotypic features have been linked to tumor cell immune escape mechanisms in PMBCL. We studied 571 B-cell lymphomas with a focus on PMBCL. Using fluorescence in situ hybridization here, we report that the programmed death ligand (PDL) locus (9p24.1) is frequently and specifically rearranged in PMBCL (20%) as compared with diffuse large B-cell lymphoma, follicular lymphoma, and Hodgkin lymphoma. Rearrangement was significantly correlated with overexpression of PDL transcripts. Utilizing high-throughput sequencing techniques, we characterized novel translocations and chimeric fusion transcripts involving PDLs at base-pair resolution. Our data suggest that recurrent genomic rearrangement events underlie an immune privilege phenotype in a subset of B-cell lymphomas.

MYC and BCL2 protein expression predicts survival in patients with diffuse large B-cell lymphoma treated with rituximab

Diffuse large B‐cell lymphoma (DLBCL) is a heterogeneous disease and “double‐hit” DLBCL, with both MYC and BCL2 translocations has a poor prognosis. In this study, we investigated whether MYC and BCL2 protein expression in tissue would predict survival in DLBCL. The study included 106 cases of de novo DLBCL treated with rituximab and cyclophosphamide, doxorubicin, vincristine and prednisone (R‐CHOP) or CHOP‐like regimens. The results were validated on an independent cohort of 205 DLBCL patients. Patients with low expression of BCL2 (≤30%) and MYC (≤50%) had the best prognosis, whereas those with high BCL2 (>30%) and MYC (>50%) had the worst outcome. In multivariate analysis, the combination of the BCL2 and MYC was an independent predictor of overall survival (OS) and event‐free survival (EFS) (P = 0·015 and P = 0·005, respectively). The risk of death was nine times greater for patients with high BCL2 and MYC compared to those with low expression. High BCL2 and MYC was a strong predictor of poor OS (P < 0·001) and EFS (P = 0·0017) in patients with the germinal centre B‐cell (GCB) type, but not in the non‐GCB type. In DLBCL, high co‐expression of MYC and BCL2 was an independent predictor of poor survival, and could be used to stratify patients for risk‐adapted therapies.

Prognostic Significance of Diffuse Large B-Cell Lymphoma Cell of Origin Determined by Digital Gene Expression in Formalin-Fixed Paraffin-Embedded Tissue Biopsies

PURPOSE To evaluate the prognostic impact of cell-of-origin (COO) subgroups, assigned using the recently described gene expression-based Lymph2Cx assay in comparison with International Prognostic Index (IPI) score and MYC/BCL2 coexpression status (dual expressers). PATIENTS AND METHODS Reproducibility of COO assignment using the Lymph2Cx assay was tested employing repeated sampling within tumor biopsies and changes in reagent lots. The assay was then applied to pretreatment formalin-fixed paraffin-embedded tissue (FFPET) biopsies from 344 patients with de novo diffuse large B-cell lymphoma (DLBCL) uniformly treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) at the British Columbia Cancer Agency. MYC and BCL2 protein expression was assessed using immunohistochemistry on tissue microarrays. RESULTS The Lymph2Cx assay provided concordant COO calls in 96% of 49 repeatedly sampled tumor biopsies and in 100% of 83 FFPET biopsies tested across reagent lots. Critically, no frank misclassification (activated B-cell-like DLBCL to germinal center B-cell-like DLBCL or vice versa) was observed. Patients with activated B-cell-like DLBCL had significantly inferior outcomes compared with patients with germinal center B-cell-like DLBCL (log-rank P < .001 for time to progression, progression-free survival, disease-specific survival, and overall survival). In pairwise multivariable analyses, COO was associated with outcomes independent of IPI score and MYC/BCL2 immunohistochemistry. The prognostic significance of COO was particularly evident in patients with intermediate IPI scores and the non-MYC-positive/BCL2-positive subgroup (log-rank P < .001 for time to progression). CONCLUSION Assignment of DLBCL COO by the Lymph2Cx assay using FFPET biopsies identifies patient groups with significantly different outcomes after R-CHOP, independent of IPI score and MYC/BCL2 dual expression.

MYC and aggressive B-cell lymphomas.

Rearrangement of the proto-oncogene MYC leads to MYC protein deregulation and is an important driver of oncogenic transformation. MYC rearrangement is a recurring genetic abnormality in several aggressive B-cell lymphomas including: Burkitt lymphoma, diffuse large B-cell lymphoma; B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma; rare de novo acute lymphoblastic lymphoma/leukemia, transformed follicular lymphoma, and plasmablastic lymphoma. Important distinctions in the role of MYC in these tumors likely reflect whether it is a primary or secondary genetic event. The presence of a MYC rearrangement in these diseases has diagnostic and prognostic implications and it is important for the practicing anatomic pathologist to be familiar with these issues when diagnosing aggressive B-cell lymphomas. This review provides a brief overview of MYC biology; shows the clinical and pathologic features of the aggressive B-cell lymphomas that harbor recurrent MYC rearrangements; explores the diagnostic and clinical implications of MYC rearrangements in these diseases; and outlines the techniques available to the anatomic pathologist to detect MYC deregulation.

CD30 expression in de novo diffuse large B-cell lymphoma: a population-based study from British Columbia.

Diffuse large B‐cell lymphoma (DLBCL) is a heterogeneous disease with variable therapeutic responses and alternative therapies are needed for patients with unfavourable treatment outcomes after standard treatment with R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). One promising candidate is brentuximab vedotin, an antibody‐drug conjugate targeting CD30‐expressing cells. However, CD30 (TNFRSF8) expression patterns in DLBCL are not well described thus far. Here, we examined CD30 expression in a population‐based cohort of immunocompetent patients from British Columbia with de novo DLBCL using immunohistochemistry. 385 cases of formalin‐fixed paraffin‐embedded DLBCL in tissue microarrays were evaluated. 95 cases (25%) harboured CD30+ tumour cells. Using a > 0% cut‐off, CD30 expression was predictive of superior 5‐year progression‐free survival within R‐CHOP treated germinal centre B‐cell‐like (GCB) DLBCL (86% vs. 64%, P = 0·020), which was independent of the International Prognostic Index. Epstein‐Barr virus (EBV) was identified in 11 (3%) cases, all of which were non‐GCB (P = 0·001) and almost exclusively positive for CD30 expression (10/11) (P < 0·001). We conclude CD30 is expressed in a substantial proportion of DLBCL and CD30 immunohistochemistry may be a useful prognostic marker in R‐CHOP treated GCB‐DLBCL. The significant association of CD30 with EBV‐positive non‐GCB DLBCL suggests a distinct pathobiology for these cases.

The Prognostic Impact of CD163-Positive Macrophages in Follicular Lymphoma: A Study from the BC Cancer Agency and the Lymphoma Study Association

Purpose: We aimed to assess the prognostic significance of follicular lymphoma–associated macrophages in the era of rituximab treatment and maintenance. Experimental Design: We applied immunohistochemistry for CD68 and CD163 to two large tissue microarrays (TMA). The first TMA included samples from 186 patients from the BC Cancer Agency (BCCA) who had been treated with first-line systemic treatment including rituximab, cyclophosphamide, vincristine, and prednisone. The second contained 395 samples from PRIMA trial patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone, and randomized to rituximab maintenance or observation. Macrophage infiltration was assessed using Aperio image analysis. Each of the two cohorts was randomly split into training/validation sets. Results: An increased CD163-positive pixel count was predictive of adverse outcome in the BCCA dataset [5-year progression-free survival (PFS) 38% vs. 72%, respectively, P = 0.004 in the training cohort and 5-year PFS 29% vs. 61%, respectively, P = 0.004 in the validation cohort]. In the PRIMA trial, an increased CD163 pixel count was associated with favorable outcome (5-year PFS 60% vs. 44%, respectively, P = 0.011 in the training cohort and 5-year PFS 55% vs. 37%, respectively, P = 0.030 in the validation cohort). Conclusions: CD163-positive macrophages predict outcome in follicular lymphoma, but their prognostic impact is highly dependent on treatment received. Clin Cancer Res; 21(15); 3428–35. ©2015 AACR.

Outcomes in splenic marginal zone lymphoma: analysis of 107 patients treated in British Columbia

Splenic marginal zone lymphoma (SMZL) accounts for less than 2% of all non‐Hodgkin lymphomas. We identified 107 cases diagnosed with SMZL between 1985 and 2012 from the British Columbia Cancer Agency Centre for Lymphoid Cancer and Lymphoma Pathology Databases. Patient characteristics were: median age 67 years (range 30–88), male 40%, stage IV 98%, splenomegaly 93%, bone marrow involvement 96%, peripheral blood involvement 87%. As initial treatment, 52 underwent splenectomy (10 with chemotherapy), 38 chemotherapy alone (21 chemoimmunotherapy containing rituximab, 1 rituximab alone), two antivirals for hepatitis C, and 15 were only observed. The 10‐year overall survival for first‐line splenectomy versus chemotherapy was 61% and 42%, respectively [Hazard Ratio (HR) 0·48, 95% confidence interval (CI) 0·26–0·88, P = 0·017]. The 10‐year failure‐free survival (FFS) after first‐line splenectomy vs chemotherapy was 39% and 14%, respectively (HR 0·48, 95% CI 0·28–0·80, P = 0·004). Among the 38 patients who received first‐line chemotherapy, FFS was similar between those receiving rituximab (n = 22) and those who did not (n = 16) (HR 0·64, 95% CI 0·31–1·34, P = 0·238). Fifteen patients transformed to aggressive lymphoma with median time to transformation of 3·5 years (range 6 months to 12 years) and the 10‐year transformation rate was 18%. In conclusion, splenectomy remains a reasonable treatment for patients with SMZL.

EBV may be expressed in the LP cells of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) in both children and adults

Nodular lymphocyte–predominant Hodgkin lymphoma (NLPHL) and classical Hodgkin lymphoma (CHL) are classified separately because of their distinct clinical and pathologic features. Whereas Epstein-Barr virus (EBV) is detected in the neoplastic cells of 25% to 70% of CHL, NLPHL is generally considered to be EBV−. We assessed EBV status in 302 pediatric and adult cases of NLPHL. A total of 145 pediatric (age 18 y or younger) and 157 adult cases of NLPHL were retrieved from 3 North American centers and tested for EBV by in situ hybridization (EBV-encoded small RNA). Clinical and pathologic features were analyzed. Five (3.4%) pediatric and 7 (4.5%) adult NLPHL cases contained EBV+ lymphocyte-predominant (LP) cells. Although all 12 cases met the criteria for diagnosis of NLPHL, atypical features were present, including capsular fibrosis, atrophic germinal centers, and pleomorphic or atypical LP cells. CD20 and OCT-2 were strongly and diffusely positive in all except 1 case. However, PAX5 and CD79a were weak and/or variable in 7/8 and 6/6 cases tested, respectively. EBV+ cases were more likely to be CD30+ (75%) compared with EBV− cases (25%) (P=0.0007); CD15 was negative in all cases. Our results show that EBV+ LP cells may occur in NLPHL. Distinguishing EBV+ NLPHL from CHL can be challenging, as EBV+ NLPHL can have partial expression of CD30 and weak PAX5 staining as well as pleomorphic-appearing LP cells. However, the overall appearance and maintenance of B-cell phenotype, with strong and diffuse CD20 and OCT-2 expression, support the diagnosis of NLPHL in these cases.