[Detection of 3q27 chromosomal abnormality in diffuse large B cell lymphoma using FISH on cell microarray].

OBJECTIVE

To investigate the association of 3q27 chromosome rearrangement with bcl-6 gene amplification and the molecular classification, therapeutic efficacies, and clinical stages in diffuse large B cell lymphoma (DLBC).

METHODS

The newly invented cell microarray was used to detect 3q27 chromosome rearrangement and bcl-6 gene amplification in 60 cases of DLBCL by fluorescence in situ hybridization (FISH). The molecular classification of germinal center B-cell-like (GCB) and non-germinal center B-cell-like (non-GCB) was investigated by analyzing the expression of CD20, CD10, bcl-6 and MUM1 simultaneously by immunohistochemical S-P method and tissue microarray. The information of therapeutic efficacies and clinical stages was obtained by analyzing clinical cases. The relationships among the factors were analyzed by statistics.

RESULTS

In 60 cases of DLBCL, 48.3%(29/60) were GCB and 51.7%(31/60) were non-GCB. The 3q27 chromosome rearrangement and bcl-6 gene amplification were present in 15 and 22 cases respectively. In 15 cases with 3q27 rearrangement, bcl-6 protein expression was positive in 3(20.0%), which was significantly different from that in cases without 3q27 rearrangement (P=0.017). In 60 cases of DLBCL, bcl-6 gene amplification was present in 22 cases, in which 5(22.7%) were GCB and 17(77.3%) were non-GCB, which was significantly different from that in cases without bcl-6 gene amplification (P=0.003). In 36 cases undergoing the normal CHOP program treatment, bcl-6 gene amplification was present in 15 cases and the rates of the complete remission, partial remission and no change were 4(26.7%), 4(26.7%) and 7(46.7%) respectively, and again it was significantly different from that in cases without bcl-6 gene amplification (P=0.016). There were no statistical significances among bcl-6 gene, BCL-6 protein expression, and clinical stages. Cases with BCL-6 protein positive and negative expression were not correlated with therapeutic efficacies and clinical stages.

CONCLUSION

There is lower expression of BCL-6 protein in cases with bcl-6 gene fragmentation. Cases with bcl-6 gene amplification are non-GCB with worse therapeutic results and later clinical stages. There may be other genes near chromosome 3q27 associated with DLBCL prognosis.