Translocation detection in lymphoma diagnosis by split-signal FISH: a standardised approach

Lymphomas originating from the lymphatic system comprise about 30 entities classified according to the World Health Organization (WHO). The histopathological diagnosis is generally considered difficult and prone to mistakes. Since non-random chromosomal translocations are specifically involved in different lymphoma entities, their detection will be increasingly important. Hence, a split-signal fluorescence in situ hybridisation (FISH) procedure would be helpful in discriminating the most difficult classifications. The Euro-FISH programme, a concerted action of nine European laboratories, has validated a robust, standardised protocol to improve the diagnostic approach on lymphoma entities. Therefore, 16 fluorescent probes and 10 WHO entities, supplemented with reactive cases, were selected. The results of the Euro-FISH programme show that all probes were correctly cytogenetically located, that the standardised protocol is robust, resulting in reliable results in approximately 90% of cases, and that the procedure could be implemented in every laboratory, bringing the relatively easy interpretation of split-signal probes within the reach of many pathology laboratories

Prognostic Significance of MYC Rearrangement and Translocation Partner in Diffuse Large B-Cell Lymphoma : A Study by the Lunenburg Lymphoma Biomarker Consortium

PURPOSE: MYC rearrangement (MYC-R) occurs in approximately 10% of diffuse large B-cell lymphomas (DLBCLs) and has been associated with poor prognosis in many studies. The impact of MYC-R on prognosis may be influenced by the MYC partner gene (immunoglobulin [IG] or a non-IG gene). We evaluated a large cohort of patients through the Lunenburg Lymphoma Biomarker Consortium to validate the prognostic significance of MYC-R (single-, double-, and triple-hit status) in DLBCL within the context of the MYC partner gene. METHODS: The study cohort included patients with histologically confirmed DLBCL morphology derived from large prospective trials and patient registries in Europe and North America who were uniformly treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone therapy or the like. Fluorescence in situ hybridization for the MYC, BCL2, BCL6, and IG heavy and light chain loci was used, and results were correlated with clinical outcomes. RESULTS: A total of 5,117 patients were identified of whom 2,383 (47%) had biopsy material available to assess for MYC-R. MYC-R was present in 264 (11%) of 2,383 patients and was associated with a significantly shorter progression-free and overall survival, with a strong time-dependent effect within the first 24 months after diagnosis. The adverse prognostic impact of MYC-R was only evident in patients with a concurrent rearrangement of BCL2 and/or BCL6 and an IG partner (hazard ratio, 2.4; 95% CI, 1.6 to 3.6; P < .001). CONCLUSION: The negative prognostic impact of MYC-R in DLBCL is largely observed in patients with MYC double hit/triple-hit disease in which MYC is translocated to an IG partner, and this effect is restricted to the first 2 years after diagnosis. Our results suggest that diagnostic strategies should be adopted to identify this high-risk cohort, and risk-adjusted therapeutic approaches should be refined further

Primary Cutaneous Follicle Center Lymphomas Expressing BCL2 Protein Frequently Harbor BCL2 Gene Break and May Present 1p36 Deletion

International audienceThe classification of cutaneous follicular lymphoma (CFL) into primary cutaneous follicle center lymphoma (PCFCL) or secondary cutaneous follicular lymphoma (SCFL) is challenging. SCFL is suspected when tumor cells express BCL2 protein, reflecting a BCL2 translocation. However, BCL2 expression is difficult to assess in CFLs because of numerous BCL2+ reactive T cells. To investigate these issues and to further characterize PCFCL, we studied a series of 25 CFLs without any extracutaneous disease at diagnosis, selected on the basis of BCL2 protein expression using 2 BCL2 antibodies (clones 124 and E17) and BOB1/BCL2 double immunostaining. All cases were studied using interphase fluorescence in situ hybridization with BCL2, BCL6, IGH, IGK, IGL breakapart, IGH-BCL2 fusion, and 1p36/1q25 dual-color probes. Nineteen CFLs were BCL2 positive, and 6 were negative. After a medium follow-up of 24 (6 to 96) months, 5 cases were reclassified as SCFL and were excluded from a part of our analyses. Among BCL2+ PCFCLs, 60% (9/15) demonstrated a BCL2 break. BCL2-break-positive cases had a tendency to occur in the head and neck and showed the classical phenotype of nodal follicular lymphoma (CD10+, BCL6+, BCL2+, STMN+) compared with BCL2-break-negative PCFCLs. Del 1p36 was observed in 1 PCFCL. No significant clinical differences were observed between BCL2+ or BCL2- PCFCL. In conclusion, we show that a subset of PCFCLs harbor similar genetic alterations, as observed in nodal follicular lymphomas, including BCL2 breaks and 1p36 deletion. As BCL2 protein expression is usually associated with the presence of a BCL2 translocation, fluorescence in situ hybridization should be performed to confirm this hypothesis

Complete remission of gastric Burkitt’s lymphoma after eradication of Helicobacter pylori

Burkitt’s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemotherapy. Occurrence at the gastric site is rare. We report the case of a 39-year old woman who presented with a prominent ulcerated lesion of the antrum corresponding histologically to a Burkitt’s lymphoma associated with Helicobacter pylori (H pylori) infection. Interphase fluorescence in situ hybridization (FISH) demonstrated c-MYC gene rearrangement in tumour cells without BCL2 or BCL6 gene translocations. Ulcer healing and tumour regression with a complete histological response were obtained 8 wk after H pylori eradication. In spite of this complete remission, taking into account the high risk of recurrence, the patient received systemic and intrathecal chemotherapy. Two years later, the patient remained in complete remission. This is the first report of a gastric Burkitt’s lymphoma responding to H pylori eradication. These findings raise the question of the potential role of H pylori in the pathogenesis of some gastric Burkitt’s lymphomas, and show the importance of searching for and eradicating the bacteria in combination with conventional chemotherapy regimens

Primary mucosa-associated lymphoid tissue lymphoma of the gallbladder: report of a case harboring API2/MALT1 gene fusion.

The genetic alterations underlying extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue type are heterogeneous and show variation according to the tumor site. Here, we report a case of mucosa-associated lymphoid tissue lymphoma of the gallbladder with genetic characterization. This lymphoma, diagnosed in a 75-year-old woman who underwent cholecystectomy for suspected acute cholecystitis, presented as diffuse thickening of the gallbladder wall. The morphology was typical of mucosa-associated lymphoid tissue lymphoma, and by immunophenotype, the tumor cells were CD20+ CD5- CD10- CD23- CD43- BCL6- BCL2+ IgM+ IgD- lambda+, with moderate nuclear expression of BCL10. Interphase fluorescence in situ hybridization analysis on paraffin sections, using a fusion probe for API2/MALT1, demonstrated 2 fusion signals in most nuclei, bringing the first documentation of a t(11;18)(q21;q21) in this exceptional primary disease location

Is Elevated Gastric Tissue NOX2 Associated with Lymphoma of Mucosa-Associated Lymphoid Tissue?

International audienceAbstract Helicobacter pylori infection plays a crucial role in the pathogenesis of gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). However, the host response to this infection is also important in the development of the disease. In particular, NADPH oxidases (NOXs) which generate reactive oxygen species are known to induce cell damage possibly leading to carcinogenesis. We analyze for the first time NOX expression in a series of well characterized gastric MALT lymphoma (GML) patients in comparison with controls. Our observation leads to the hypothesis that NOX2 expression is significantly associated with GML. Antioxid. Redox Signal. 16, 1205-1211

Occurrence of minimal change nephrotic syndrome in classical Hodgkin lymphoma is closely related to the induction of c-mip in Hodgkin-Reed Sternberg cells and podocytes.

International audienceIt is currently considered that idiopathic minimal change nephrotic syndrome is an immune-mediated glomerular disease. Its association with classical Hodgkin lymphoma minimal change nephrotic syndrome (cHL-MCNS) suggests a molecular link, which remains to be elucidated. We analyzed the expression of cmaf inducing protein (c-mip) in lymphomatous tissues and kidney biopsy samples of patients with cHL-MCNS (n = 8) and in lymphomatous tissues of patients with isolated cHL (n = 9). Because c-mip affects the regulatory loop involving Fyn, we investigated possible structural defects in this signaling pathway, using laser capture microdissection, reverse transcription polymerase chain reaction, and Western blotting. We found that c-mip was selectively expressed in Hodgkin and Reed-Sternberg (HRS) cells and podocytes of patients with cHL-MCNS but is undetectable in patients with isolated cHL. We demonstrated that c-mip was specifically involved in the negative regulation of early proximal signaling through its interaction with phosphoprotein associated with glycosphingolipid-enriched microdomains and Fyn. We showed that the up-regulation of c-mip in cHL-MCNS was associated with a possible Fyn defect in HRS cells and podocytes. Moreover, we showed that c-mip was up-regulated in Fyn-deficient podocytes. c-mip may be a useful marker of cHL-MCNS and its induction reflects the dysregulation of proximal signaling