Epstein-Barr virus and Burkitt lymphoma

Burkitt lymphoma (BL) is an aggressive B-cell malignancy with endemic, sporadic and immunodeficiency-associated variants. It has been known for many years that the fundamental transforming event in BL is the translocation of the MYC gene, and the events that bring about this translocation and those that allow cells to survive with the constitutive expression of MYC have been the subject of intense investigation. Epstein-Barr virus (EBV) infection, malaria, immunodeficiency and spontaneous, somatic mutation can all contribute to the origin and maintenance of this cancer and their mechanisms are the subject of this review.     

Variant translocation in Burkitt lymphoma

The demonstration of a t(2;8) (p12;q23) in a typical nonendemic Burkitt lymphoma (BL) in a European Caucasian child, provides evidence that variant translocations can be found in this type of malignancy as well as in other malignant hemopathies, particularly those with a Ph¹ chromosome. This observation is important when studying the significance of non-randomly occurring chromosome anomalies in human malignancies. Thus it appears that in certain human hemopathies, e.g., chronic myelocytic leukemia and BL, the deletion of a specific chromosome, nos. 22 and 8, respectively, may be the key karyotypic event associated with the disease, rather than the site of translocation of the deleted segments.     

Burkitt lymphoma and genetic markers of immunoglobulin

The Ig allotype G3m (c3) was numerically more frequent among 70 Kenyan Burkitt lymphoma (BL) cases than in 70 Kenyans with other tumors of the neck (0.02 greater than p greater than 0.01). The distribution of allotypes G1m (a, x) and G3m (b5) did not differ between 50 Caucasian BL cases and blood donors.     

Comparative immunohistochemical analysis of pediatric Burkitt lymphoma and diffuse large B-cell lymphoma

Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) account for nearly all pediatric nonlymphoblastic B-cell lymphomas. Because clinical behavior, prognosis, and response to therapy might differ, diagnostic accuracy is important. Morphologic examination often is sufficient, but occasionally, diagnostic ancillary studies are required. In adults, immunophenotyping is useful; however, pediatric data are limited. We characterized the immunohistochemical expression of 6 proteins (c-myc, CD10, bcl-6, bcl-2, CD138, and MIB-1) in pediatric BL (33 cases) and DLBCL (20 cases) with classic morphologic features. Significant differences in c-myc (BL, 30/33 [91%] vs DLBCL, 5/20 [25%]; P < .0001), bcl-2 (BL, 1/25 [4%] vs DLBCL, 7/19 [37%]; P < .02), and mean MIB-1 (BL, 99% vs DLBCL, 56%; P < .0001) expression were observed. There were no significant differences for CD10 (100% expression in BL and DLBCL), bcl-6 (BL, 23/33 [70%] vs DLBCL, 15/20 [75%]), or CD138 (no expression). Thus, pediatric BL and DLBCL have distinctive immunohistochemical profiles, and staining for c-myc, MIB-1, and bcl-2 might be useful in morphologically difficult cases.     

De novo CD5+ Burkitt lymphoma/leukemia

CD5 is a T-cell marker aberrantly expressed in B-cell chronic lymphocytic leukemia and mantle cell lymphoma. Other B-cell neoplasms, including Burkitt lymphoma, are usually CD5-. We report 4 cases of de novo CD5+ Burkitt lymphoma/leukemia in elderly patients, all of whom were in a leukemic phase and had variable lymph node and splenic involvement. The blasts were typically medium sized, with folded nuclei, distinct but not prominent nucleoli, and moderate amounts of somewhat vacuolated basophilic cytoplasm; they were terminal deoxynucleotidyl transferase--negative and surface immunoglobulin--positive. All 4 cases demonstrated c-myc rearrangement, but none had t(14;18), t(11;14), or cyclin D1 overexpression or rearrangement. Only 1 patient achieved complete remission after hyper-CVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone) therapy. One patient responded poorly to hyper-CVAD, and 2 patients died during induction chemotherapy. These rare cases of aggressive lymphoid malignancy with CD5 positivity and molecular features associated with Burkitt lymphoma/leukemia are best classified as Burkitt leukemia. However, the morphologic and immunophenotypic similarity to the blastoid variant of mantle cell lymphoma are diagnostically challenging. The diseases can be distinguished at the genetic level, since Burkitt lymphoma involves the rearrangement of c-myc, and mantle cell lymphoma usually the overexpression or rearrangement of cyclin D1.     

Serial cytogenetic alterations resulting in transformation of a low-grade follicular lymphoma to Burkitt lymphoma

Follicular lymphoma (FL) is the most common indolent or low-grade non-Hodgkin lymphoma (NHL). Histologic transformation to high-grade lymphoma, generally to diffuse large B-cell lymphoma, occurs in 25–35% of cases. Although t(14;18), the cytogenetic hallmark of FL, has been found in 85% of these cases, multiple secondary cytogenetic and molecular genetic changes underlie the transformation process. We report the case of a 58-year-old patient who presented with stage IVA, grade 2 FL that subsequently transformed to Burkitt lymphoma. Multiple chromosomal aberrations, including three novel translocations, were observed related to this transformation. Inversion (1)(p36.3q12) and t(3;14;18)(p23;q32;q21) occurred prior to transformation and may have contributed to the transformation process. A t(1;11)(q25;q13) was acquired simultaneously with t(8;22) and, in conjunction with other chromosomal abnormalities, coincided with an extremely aggressive clinical course. The frequent breakage of 1q observed in this case suggests that the region harbors important genomic signals for the transformation of FL.     

Burkitt lymphoma following splenic marginal zone lymphoma. evidence for two independent B-cell clones

We report the progression of splenic marginal zone lymphoma (SMZL) with circulating villous lymphocytes to Burkitt lymphoma with the presence of a t(8;14)(q24;q32) followed by a highly aggressive course. While the initial indolent lymphoma had an IgM lambda immunophenotype the Burkitt lymphoma was IgM kappa-positive. Immunoglobulin heavy chain gene (IGH) sequence analysis showed no identity between the two clones. We conclude that Burkitt lymphoma can occur in patients with SMZL, although not necessarily of identical clonal origin.     

The distinction between Burkitt lymphoma and diffuse large B-Cell lymphoma with c-myc rearrangement.

To compare immunophenotypic and molecular features between Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) with c-myc rearrangements (c-mycR DLBCL), we analyzed 18 cases of B-cell non-Hodgkin's lymphoma with c-mycR that were confirmed by chromosomal and/or Southern blotting analyses. The cases were histologically classified into 10 BLs and five DLBCLs. The remaining three cases could not be classified because of suboptimal quality of the surgical materials. BLs were from five adults and five children, whereas all DLBCLs were from adults. BLs were positive for CD20 (10/10 cases examined), CD10 (9/10), Bcl-2 (1/9), and Bcl-6 (10/10), whereas they were negative for CD3 (0/10) and EBV (0/8), by Epstein-Barr virus (EBV) EBER-1 RNA in situ hybridization. c-MycR DLBCLs were positive for CD20 (5/5), CD10 (2/5), Bcl-2 (3/4), and Bcl-6 (4/4), whereas none of them were positive for CD3 and EBV. A mean of MIB-1 index (MIB-1+ cells/neoplastic cells, %) of BLs (98.1%) was higher than that of c-mycR DLBCLs (66.3%; P <.0001). Somatic mutation of immunoglobulin heavy-chain gene variable region (VH gene) in BLs (four cases) ranged from 0.7 to 4.9% with an average value of 2.3%, whereas those in DLBCLs (three cases) from 8.2 to 32.0% with an average value of 17.0%. It is, therefore, concluded that a growth fraction of nearly 100%, as well as a monotonous proliferation of medium-sized cells and c-myc(R), should be of value in the diagnosis of BL, which is probably different from c-myc(R) DLBCL. In addition, CD10+, Bcl-2-, and low frequency of mutation of the VH gene could be helpful for the histologic distinction of BL from (c-mycR) DLBCL.     

Burkitt lymphoma with unusual granulomatous reaction. A case report

Formation of epithelioid histiocytic cell granulomas has been described in the post in various neoplasms, hematologic malignancies included. Among lymphoproliferative disorders such changes are commonly found in Hodgkin lymphoma and T-cell non-Hodgkin lymphomas (NHL), but are rarely described in B-NHL, like Burkitt lymphoma. This report presents a case of sporadic Burkitt lymphoma accompanied by a sarcoid-like reaction without any clinical, laboratory or histological evidence of microorganisms nor sarcoidosis. Using in situ hybridization and polymerase chain reaction the presence of the Epstein-Barr virus (EBV) was detected in the analyzed lymphoma cells. EBV demonstrated latency I phenotype as defined by the lack of immunohistochemical positivity of latent membrane protein 1 (LMP1). Cytogenetic investigation using fluorescence in situ hybridization uncovered c-MYC mutation and provided indirect indication for the MYC/IgL fusion gene. The lack of EBV positivity in histiocytes indicated the reactive character of the granulomatous reaction in relation to the neoplasm. The role of the granulomatous reaction in the biology and prognosis of Burkitt lymphoma and the function of EBV infection in its development remain to be established.     

Low expression of miR-150 in pediatric intestinal Burkitt lymphoma

BackgroundBurkitt lymphoma (BL) is a highly aggressive B-cell lymphoma with rapid proliferation. It has become evident that miRNAs are involved in hematopoietic malignancies. This study was undertaken to investigate the miRNA expression patterns of pediatric intestinal BL tissues.MethodsWe collected 28 BL and 8 reactive lymphoid hyperplasia (RLH) samples. miRNA expression profiling was performed in BL and RLH tissues to identify BL-related miRNAs, which were further analyzed by qRT-PCR and miRNA-ISH. In addition, immunohistochemistry (IHC) and western blot were used to define the protein targets of the BL-related miRNAs. Furthermore, we evaluated cell growth status by using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay in Raji cell line, which was transected with the BL-related miRNA mimics or inhibitors.ResultsmiRNA expression profiling showed that miR-150 had extremely decreased expression levels in BL patients. In both ISH and qRT-PCR analyses, BL had reduced levels of miR-150 expression compared with RLH. However, there is no significant correlation of miR-150 expression and EBV status in BL. Moreover, IHC and western blotting defined that c-Myb and Survivin are the protein targets of miR-150. Re-expression of miR-150 reduced the proliferation of Raji cells.ConclusionsDeregulation of miR-150 may be useful as a diagnostic tool in BL, based on miRNA profile screening, qRT-PCR and miRNA-ISH. miR-150 plays an important role in BL by targeting c-Myb and Survivin. Re-expression of miR-150 reduced the proliferation of Raji cells, which suggests it to be a promising novel candidate for tumor treatment.     

Primary central nervous system B cell lymphoma with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma

B cell lymphoma with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma (DLBCL/BL) is a new lymphoma entity which is recognized in the current World Health Organization (WHO) classification (2008). We report a case of a primary central nervous system lymphoma (PCNSL) with findings consistent with DLBCL/BL. It is characterized by a very aggressive clinical course, and a widespread multifocal involvement of the CNS. Our case shows that a DLBCL/BL can manifest in the CNS alone without any systemic involvement.     

TCL1 expression and Epstein-Barr virus status in pediatric Burkitt lymphoma

Elevated T-cell leukemia-1 (TCL1) oncoprotein expression might promote human Burkitt lymphoma (BL) because increased TCL1 causes Burkitt-like lymphomas in TCL1 transgenic mice. Epstein-Barr virus (EBV) infection has been implicated as a cause of increased TCL1 expression in multiple BL cell lines, suggesting a critical connection between EBV and TCL1-induced BL. The TCL1 expression and EBV status of 14 sporadic pediatric BL cases was determined by immunohistochemical staining for TCL1 and in situ hybridization for EBV-encoded RNA (EBER). Our results showed TCL1 protein in 11 cases, predominantly in the nucleus with strong-intensity staining. EBER was positive in 4 cases, with 3 of these cases also TCL1+. In the 10 cases that were EBER-, TCL1 was strongly positive in 8. These data indicate that the TCL1 oncoprotein is expressed strongly in most pediatric BL cases. However, persistent EBV is not essential for increased TCL1 expression, although elevated TCL1 and c-MYC coexpression might cooperate in the development of most pediatric and adult BL cases.     

Pattern of hemoglobin concentration in untreated Burkitt lymphoma patients in Ibadan.

Hemoglobin concentration is studied in 128 untreated Burkitt lymphoma patients in Ibadan. While there is no significant diagnostic pattern in hemoglobin concentration, Burkitt lymphoma patients show marked anemia as compared with healthy adult Nigerians. The degree of involvement of malarial parasitemia in producing anemia in Burkitt lymphoma patients has yet to be determined.     

Primary bi-atrial Burkitt lymphoma with severe inflow impairment in an immunocompetent patient

We report herein a case of sporadic primary cardiac bi-atrial Burkitt lymphoma (BL) occurred in a 67-year-old white immunocompetent patient and presenting with signs and symptoms of severe bilateral atrioventricular inflow impairment. Extranodal BL involving the heart is rare and seldom recognized clinically. Delayed discovery contributes to significant mortality. In the case presented extended surgical excision and intensive combination chemotherapy regiments resulted in complete remission at 1 year.     

IL-6和AG490对Burkitt淋巴瘤细胞生长的影响

 目的: 观察IL-6和AG490对Raji细胞生长的影响,探讨信号转导及转录激活因子3(STAT3)及survivin在Burkitt淋巴瘤发生发展中的作用,为寻找淋巴瘤生物治疗的新靶标提供实验依据。方法: 培养Raji细胞,分别加入STAT3的激动剂IL-6和抑制剂AG490,用real-time PCR和Western blot检测STAT3、survivin的表达情况及STAT3的磷酸化,MTT法检查细胞活力,流式细胞术检测细胞凋亡和细胞周期变化。结果: 培养细胞中加入IL-6或AG490后,细胞生长受明显影响并呈现药物浓度依赖关系(P<0.05);与相应的对照组比较,IL-6组Raji细胞中STAT3、survivin mRNA的表达明显升高,AG490组Raij细胞中STAT3、survivin的mRNA表达明显降低。不同浓度的IL-6组之间、不同浓度的AG490组之间,STAT3和survivin mRNA的表达亦有显著差异(P<0.05),且2种基因mRNA表达都呈现出药物浓度依赖关系。p-STAT3、STAT3和survivin的蛋白水平在IL-6作用下表达增高,AG490作用下表达降低;细胞凋亡率在IL-6作用下逐渐降低,在AG490作用下逐渐升高,且都呈现出药物浓度依赖关系;经AG490处理后,G₁期Raji细胞明显增加,S期细胞无明显改变,G₁/S比值增加,而在IL-6组中,S期细胞明显降低。结论: IL-6和AG490对Raji细胞生长有明显影响,STAT3及其下游靶基因survivin的表达改变可能是IL-6及AG490影响Raji细胞生长的重要分子机制。