Detection of t (14; 18) translocation and bcl-2 amplification in diffuse large B-cell lymphoma / 中华病理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the role of t (14; 18) chromosomal translocation and bcl-2 amplification in classification, clinical staging and prognostic evaluation of diffuse large B cell lymphoma (DLBCL).</p><p><b>METHODS</b>Sixty cases of DLBCL were included in this investigation. Microdissection of the lymphoma tissue was performed. Tissue microarray and in-situ fluorescence hybridization technique were used to detect t (14; 18) and bcl-2 amplification. The phenotypes of either germinal center B-cell-like (GCB) or non-germinal center B-cell-like (non-GCB) were determined by immunohistochemistry including CD20, CD10, bcl-6 and MUM1 (S-P method) using the tissue microarray format. Clinical staging and therapeutic response were obtained by medical record review. The relationships among different parameters were analyzed by appropriate statistical methods.</p><p><b>RESULTS</b>Among 60 cases of DLBCL, bcl-2/IgH was positive in 10 cases and bcl-2 gene amplification was detected in 18 cases. Overall, 29 (48.3%) cases were GCB and 31 (51.7%) cases were non-GCB. The t (14; 18) was seen in 8 (80.0%) cases of GCB and 2 (20.0%) of non-GCB. The difference was statistical significance (P = 0.031). Over-expression of bcl-2 was seen in all cases having both t (14; 18) and bcl-2 gene amplification. Of thirty-six patients who underwent routine CHOP treatment, bcl-2 gene amplification was seen in 13 cases. In these cases, the rates of complete remission, partial remission and no change were 3 (23.1%), 4 (30.8%) and 6 (46.2%) respectively, and the clinical stages were stage I - II (1 case, 7.7%) and stage III - IV (12 cases, 92.3%). The clinical stages and therapeutic response were significantly different between the bcl-2 amplification cases and those without (P = 0.046 and P = 0.019, respectively).</p><p><b>CONCLUSIONS</b>T (14; 18) and/or bcl-2 gene amplification can lead to an over-expression of bcl-2 protein. The bcl-2 gene amplification correlates with worse therapeutic efficacies and advanced clinical stages. The reason for the correlation between bcl-2 over-expression and the prognosis is unclear, although it may be explained by different mechanisms that lead to bcl-2 over-expression. Detection of t (14; 18) chromosome translocation by FISH can be helpful in the classification of DLBCL.</p>