Genetic and Functional Drivers of Diffuse Large B Cell Lymphoma.

Diffuse large B cell lymphoma (DLBCL) is the most common form of blood cancer and is characterized by a striking degree of genetic and clinical heterogeneity. This heterogeneity poses a major barrier to understanding the genetic basis of the disease and its response to therapy. Here, we performed an integrative analysis of whole-exome sequencing and transcriptome sequencing in a cohort of 1,001 DLBCL patients to comprehensively define the landscape of 150 genetic drivers of the disease. We characterized the functional impact of these genes using an unbiased CRISPR screen of DLBCL cell lines to define oncogenes that promote cell growth. A prognostic model comprising these genetic alterations outperformed current established methods: cell of origin, the International Prognostic Index comprising clinical variables, and dual MYC and BCL2 expression. These results comprehensively define the genetic drivers and their functional roles in DLBCL to identify new therapeutic opportunities in the disease.

Analysis of Peripheral T-cell Lymphoma Diagnostic Workup in the United States.

BACKGROUND: With increased understanding of the unique entities, subtype-specific approaches for peripheral T-cell lymphoma (PTCL) are emerging, and more precise diagnoses are becoming increasingly important. PATIENTS AND METHODS: We analyzed the approach to the histopathologic diagnosis of PTCL using data from the comprehensive oncology measures of peripheral T-cell lymphoma (COMPLETE) study. The COMPLETE trial is a large prospective cohort study of patients with newly diagnosed PTCL in the United States. RESULTS: A total of 499 patients were enrolled from 40 academic and 15 community-based centers. Baseline assessment forms were collected for 493 patients, of which 435 (88%) were available for analysis. The most common diagnoses were PTCL, not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma, and angioimmunoblastic T-cell lymphoma (AITL). A mean of 10 markers (range, 0-21) was assessed per patient. CD30 was assessed frequently but not uniformly in cases that were not anaplastic large cell lymphoma. Only 17% of PTCL-NOS cases were assessed for PD1. CXCL13 was a relatively sensitive marker in AITL, expressed in 84% of tested cases; however, only 3% of PTCL-NOS cases were tested. T follicular helper cell marker assessment differed between academic and community practices, with PD1 more often evaluated by academic centers in cases of AITL (62% vs. 12%; P = .01). CONCLUSION: The diagnostic workup for PTCL in the United States varies widely and often lacks important phenotypic information to fully characterize the lymphoma. Gaps in testing of selected markers should be filled, given the impending revision to the World Health Organization classification. The accuracy of diagnosis will become increasingly important as we enter the era of targeted treatment for PTCL.

Lobular neoplasia diagnosed on breast Core biopsy: frequency of carcinoma on excision and implications for management.

The appropriate follow-up and treatment for patients with a core biopsy diagnosis of lobular neoplasia (atypical lobular hyperplasia or lobular carcinoma in situ) remains controversial. Several studies have attempted to address this issue, with recommendations ranging from close clinical follow-up or surveillance to mandatory surgical excision in all cases. We report the findings at our institution, where virtually every core needle biopsy diagnosis of lobular neoplasia results in follow-up excision. The goal of the study was to identify potential predictors of upgrade to a more significant lesion. We identified 76 patients over a 15-year period with a core biopsy diagnosis of pure lobular neoplasia and no other high-risk lesions. Subsequent surgical excision identified 10 cases (13%) that were upgraded to carcinoma. Upgrade diagnoses included invasive ductal carcinoma (n=1), invasive lobular carcinoma (n=4), ductal carcinoma in situ (n=3), and pleomorphic lobular carcinoma in situ (n=2). All 10 upgraded cases had imaging findings suspicious for malignancy including irregular masses, asymmetric densities, or pleomorphic calcifications. Of the 10 upgraded cases, 7 were diagnosed as lobular carcinoma in situ on core biopsy. The data support a role for radiologic-pathologic correlation in the evaluation of suspicious breast lesions and suggest that the extent of lobular neoplasia in core biopsy specimens may be an indicator of the likelihood of upgrade to carcinoma.

Comparison between melanoma gene expression score and fluorescence in situ hybridization for the classification of melanocytic lesions.

Melanoma accounts for most skin cancer-related deaths and has an increasing incidence. Accurate diagnosis and distinction from atypical nevi can be at times difficult using light microscopy alone. Fluorescence in situ hybridization (FISH) and melanoma gene expression score (myPath, Myriad Genetics) have emerged as ancillary tools to further aid in this differential diagnosis. Our aim in this study was to correlate FISH results, gene expression score, consensus histopathologic impression and clinical outcome on a series of 117 challenging melanocytic lesions collected from three separate institutions. The lesions were separated into two groups: 39 histopathologically unequivocal lesions (15 malignant, 24 benign) and 78 challenging lesions interpreted by expert consensus (27 favor malignant, 30 favor benign, and 21 ambiguous). Melanoma-FISH was performed using probes for 6p25, 11q13, 8q24, and 9p21/CEP9 and scored according to established criteria. Analysis by myPath gene expression score was performed and interpreted by the manufacturer as 'benign', 'indeterminate,' or 'malignant'. In the unequivocal group, melanoma-FISH and myPath score showed 97 and 83% agreement with the histopathologic diagnosis, respectively, with 93 and 62% sensitivity, 100 and 95% specificity, and 80% inter-test agreement. In the challenging group, FISH and the myPath score showed 70 and 64% agreement with the histopathologic interpretation, respectively, with 70% inter-test agreement and similar sensitivities and specificities. The inter-test agreement was 73% overall, excluding indeterminate results. Discordant test results occurred in 27/117 cases from both unequivocal and challenging groups. Melanoma-FISH and gene expression score are valuable ancillary tools, though both have limitations and return discordant results in a subset of cases. Follow-up studies with more extensive clinical outcome data are warranted to establish the accuracy of these tests for the classification of melanocytic lesions.

Next generation sequencing of Cytokeratin 20-negative Merkel cell carcinoma reveals ultraviolet-signature mutations and recurrent TP53 and RB1 inactivation.

Merkel cell carcinoma is a rare but highly aggressive cutaneous neuroendocrine carcinoma. Cytokeratin 20 (CK20) is expressed in ~95% of Merkel cell carcinomas and is useful for distinction from morphologically similar entities including metastatic small-cell lung carcinoma. Lack of CK20 expression may make diagnosis of Merkel cell carcinoma more challenging, and has unknown biological significance. Approximately 80% of CK20-positive Merkel cell carcinomas are associated with the oncogenic Merkel cell polyomavirus. Merkel cell carcinomas lacking Merkel cell polyomavirus display distinct genetic changes from Merkel cell polyomavirus-positive Merkel cell carcinoma, including RB1 inactivating mutations. Unlike CK20-positive Merkel cell carcinoma, the majority of CK20-negative Merkel cell carcinomas are Merkel cell polyomavirus-negative, suggesting CK20-negative Merkel cell carcinomas predominantly arise through virus-independent pathway(s) and may harbor additional genetic differences from conventional Merkel cell carcinoma. Hence, we analyzed 15 CK20-negative Merkel cell carcinoma tumors (10 Merkel cell polyomavirus-negative, four Merkel cell polyomavirus-positive, and one undetermined) using the Ion Ampliseq Comprehensive Cancer Panel, which assesses copy number alterations and mutations in 409 cancer-relevant genes. Twelve tumors displayed prioritized high-level chromosomal gains or losses (average 1.9 per tumor). Non-synonymous high-confidence somatic mutations were detected in 14 tumors (average 11.9 per tumor). Assessing all somatic coding mutations, an ultraviolet-signature mutational profile was present, and more prevalent in Merkel cell polyomavirus-negative tumors. Recurrent deleterious tumor suppressor mutations affected TP53 (9/15, 60%), RB1 (3/15, 20%), and BAP1 (2/15, 13%). Oncogenic activating mutations included PIK3CA (3/15, 20%), AKT1 (1/15, 7%) and EZH2 (1/15, 7%). In conclusion, CK20-negative Merkel cell carcinoma display overlapping genetic changes with CK20-positive Merkel cell carcinoma, including RB1 mutations restricted to Merkel cell polyomavirus-negative tumors. However, some CK20-negative Merkel cell carcinomas harbor mutations not previously described in Merkel cell carcinoma. Hence, CK20-negative Merkel cell carcinomas harbor diverse oncogenic drivers which may represent therapeutic targets in individual tumors.

Dual expression of MYC and BCL2 proteins predicts worse outcomes in diffuse large B-cell lymphoma.

Recent studies suggested that MYC and BCL2 protein co-expression is an independent indicator of poor prognosis in diffuse large B-cell lymphoma. However, the immunohistochemistry protocols for dual-expression staining and the scoring cut-offs vary by study. Sixty-nine cases of diffuse large B-cell lymphoma were evaluated for MYC and BCL2 protein expression using various cut-offs that have been recommended in prior studies. Independent of the International Prognostic Index risk group, cases with dual protein expression of BCL2 and MYC using ≥50%/40% cut-offs and ≥70%/40% had significantly shorter overall survival than cases without. It was verified in this patient population that the use of BCL2 and MYC immunohistochemistry, performed with available in vitro diagnostic-cleared antibodies, provides rapid prognostic information in patients with de novo diffuse large B-cell lymphoma. This study has practical implications for diagnostic laboratories and serves as a guide for implementation in the setting of future clinical trials.

Testicular myeloid sarcoma: a rare manifestation of acute myeloid leukemia in an infant.

Myeloid sarcoma manifesting in the testis is rare and may occur concomitantly with bone marrow disease or as a separate entity. We describe our experience with a 6-month-old boy who presented with painless scrotal swelling and was found to have bilateral testicular masses on ultrasonography. The patient underwent unilateral radical inguinal orchiectomy. Surgical pathology revealed myeloid sarcoma of the testicle. He developed peripheral blood involvement 1 week postoperatively. Bone marrow biopsy showed acute myeloid leukemia. He is in remission after 2 cycles of induction chemotherapy, local radiation therapy, and allogeneic bone marrow transplantation.

Flow cytometric analysis of cerebrospinal fluid has low diagnostic yield in samples without atypical morphology or prior history of hematologic malignancy.

OBJECTIVES: To identify pretest characteristics of cerebrospinal fluid (CSF) specimens that will allow the rational use of flow cytometric analysis (FCA) in the diagnosis of hematologic malignancy. METHODS: Retrospective data were collected on 501 consecutive CSF samples submitted for FCA. RESULTS: A positive diagnosis of hematologic malignancy was made in 41 specimens (8.2%). Blasts or atypical lymphocytes were noted on Wright-stained slides in 98% of FCA-positive specimens (40/41), and a history of a hematologic malignancy was present in 89% of specimens (34/38). All FCA-positive specimens had atypical morphology or history of hematologic malignancy. Four hundred six specimens (81%) were FCA negative. Of FCA-negative specimens, 7% (30/406) had atypical morphology, and 3% (12/404) had future central nervous system involvement seen within 30 days. CONCLUSIONS: These data support a policy in which FCA of CSF is actively discouraged unless atypical lymphocytes or blasts are seen or a history of hematologic malignancy is present.

Differential monocyte/macrophage interleukin-1ß production due to biomaterial topography requires the ß2 integrin signaling pathway.

Monocytes/macrophages are crucial mediators of the host response to biomaterials, and their level of activation can be directly affected by material characteristics. Previous work has demonstrated that primary human monocytes cultured on polytetrafluoroethylene materials of varying topography but identical surface chemistry are differentially affected. Monocytes/macrophages on biaxially-expanded polytetrafluoroethylene with an average intranodal distance of 4.4 µm (4.4-ePTFE) produced higher levels of the inflammatory cytokine interleukin-1 beta (IL-1ß) compared with monocytes/macrophages on nonporous polytetrafluoroethylene (np-PTFE). The current study provides a mechanistic understanding of this response. Scanning electron microscopy revealed that monocytes/macrophages cultured on np-PTFE were more spread than those on 4.4-ePTFE. In addition, the actin cytoskeleton and intact ß2 integrin receptors were necessary for IL-1ß production by monocytes/macrophages on 4.4-ePTFE. This IL-1ß production also required the transcription factor nuclear factor kappa-B, another component of the ß2 integrin signaling pathway, although it may not be the primary transcription factor involved. These studies demonstrate the importance of several ß2 integrin signaling components to the monocyte/macrophage response to biomaterial topography.

Biomaterial topography alters healing in vivo and monocyte/macrophage activation in vitro.

The effect of biomaterial topography on healing in vivo and monocyte/macrophage stimulation in vitro was assessed. A series of expanded polytetrafluoroethylene (ePTFE) materials were characterized by increasing average intranodal distance of 1.2 µm (1.2-ePTFE), 3.0 µm (3.0-ePTFE), and 4.4 µm (4.4-ePTFE), but presented consistent surface chemistry with nonporous PTFE (np-PTFE). Subcutaneous implantation of 4.4-ePTFE into mice resulted in a statistically thinner capsule that appeared less organized and less dense than the np-PTFE response. In vitro, isolated monocytes/macrophages cultured on np-PTFE produced low levels of interleukin 1-beta (IL-1ß), 1.2-ePTFE and 3.0-ePTFE stimulated intermediate levels, and 4.4-ePTFE stimulated a 15-fold increase over np-PTFE. Analysis of cDNA microarrays demonstrated that additional proinflammatory cytokines and chemokines, including IL-1ß, interleukin 6, tumor necrosis factor alpha, monocyte chemotactic protein 1, and macrophage inflammatory protein 1-beta, were expressed at higher levels by monocytes/macrophages cultured on 4.4-ePTFE at 4 and 24 h, respectively. Expression ratios for several genes were quantified by RT-PCR and were consistent with those from the cDNA array results. These results demonstrate the effect of biomaterial topography on early proinflammatory cytokine production and gene transcription by monocytes/macrophages in vitro and decreased fibrous capsule thickness in vivo.