Résumé
Objective@#To investigate the feasibility and value of interphase fluorescence in situ hybridization (FISH) in the pathological diagnosis, differential diagnosis and therapeutic assessment of B-cell lymphomas.@*Methods@#The cohort included 604 cases of B-cell lymphoma which were collected at West China Hospital from May 2010 to December 2016.And all were subjected to interphase FISH using 11 break apart or fusion probes (MYC, bcl-2, bcl-6, IRF4, MYC/IgH, bcl-2/IgH, CCND1/IgH, IgH, API2/MALT1, p53/ATM, and D13S319/CEP12).@*Results@#The median age of the 604 B-cell lymphoma patients was 47.7 (aged 2-90) years including 372 men and 232 women. All the cases was divided into 463 large B cell lymphomas(LBL) and 141 small B cell lymphomas, and the total interphase FISH positive rate was 59.8% (361/604). Among the 463 LBL, 12.5% (58/463), 9.5% (44/463) and 2.2% (10/463) of cases showed MYC, bcl-6 and bcl-2 gene rearrangements respectively; and 363 diffuse large B cell lymphoma (DLBCLs) were reclassified as germinal center B-cell (GCB) subtype (38.6%, 140/363) and non-GCB subtype (61.4%, 223/363) by Hans algorithm. The rearrangement rates in GCB and non-GCB DLBCL were 45.7%(64/140)and 21.5%(48/223; P=0.001), respectively. Compared to the non-GCB DLBCL, GCB DLBCL showed higher MYC and bcl-2 gene rearrangements (P=0.001). Eleven (2.4%, 11/463) cases had MYC and bcl-6 or bcl-2 gene rearrangement (double-hit lymphoma); one (0.2%, 1/463) case had MYC, bcl-6 and bcl-2 gene rearrangements (triple-hit lymphoma); two (0.4%, 2/463) cases had bcl-2 and bcl-6 gene rearrangements. MYC translocation and MYC/IgH fusion were detected in 94.2%(81/86) and 83.7%(72/86) cases of Burkitt lymphomas. IRF4 rearrangement was detected in two cases of IRF4+ LBCL. Genetic abnormalities were detected in 9/19, 100%(29/29), 30.8%(12/39) and 68.5%(37/54) cases of follicular lymphoma, mantle cell lymphoma, MALT lymphoma and chronic lymphocytic leukemia, respectively.@*Conclusions@#Interphase FISH can rapidly and accurately detect the genetic changes in B-cell lymphomas. Different genetic changes are specifically valuable to the diagnosis, differential diagnosis, prognosis evaluation and treatment guidance of various B-cell lymphomas.
Résumé
<p><b>OBJECTIVE</b>To study the clinicopathologic features and significance of aberrant CD56 expression in diffuse large B-cell lymphoma (DLBCL).</p><p><b>METHODS</b>The clinical and pathologic profiles of 10 cases of DLBCL with aberrant expression of CD56 were investigated. Immunohistochemical staining, in-situ hybridization for Epstein-Barr virus encoded RNA and gene rearrangement for IgH and Igκ were carried out.</p><p><b>RESULTS</b>There were 6 male and 4 female patients. The medium age of patients was 46 years. All of them presented with extranodal lymphoma involvement, with gastrointestinal tract being the commonest site (5/10). Histologic examination showed that most of the atypical lymphoid cells were centroblast-like and demonstrated a diffuse growth pattern. Apoptosis and necrosis were identified in some cases. Immunohistochemical study showed that the tumor cells were positive for CD20 or CD79α and aberrantly expressed CD56. Five cases had the GCB phenotype while the remaining cases had the non-GCB phenotype, according to Hans classification. Bcl-6 was positive in most cases (9/10). All cases showed a high proliferation index by Ki-67. The tumor cells were negative for CD3ε, CD138 and granzyme B. In-situ hybridization for Epstein-Barr virus encoded RNA was performed in 7 cases and none of them showed positive signals. IgH gene rearranged bands were detected in 4 cases (4/6) and Igκ was detected in 3 cases (3/6). Follow-up data were available in 8 patients. Two patients died of disease progression within 5 to 13 months after diagnosis and the other 6 patients were alive 8 to 60 months after therapy.</p><p><b>CONCLUSIONS</b>DLBCL with aberrant expression of CD56 is rare. Most of them present with extranodal involvement, show high frequency of bcl-6 expression and high proliferation index. The patients often have good response to chemotherapy.</p>