[Prognostic evaluation of P53 and BCL2 proteins in MYC/BCL2 double expression DLBCL]

Objective: To investigate the strong expression (S+) of P53 and BCL2 proteins in MYC/BCL2 double-expression DLBCL (DEL) and whether they can be used for the prognostic evaluation and stratified diagnosis of DELs. Methods: Tissue microarray were made by filed FFPE blocks of 174 DLBCL cases. The translocation of MYC, BCL2 and BCL6 genes were detected by FISH, and the proteins were detected by IHC. Data of clinicopathologic features and follow up of patients were collected and OS (overall survival) and PFS (progression free survival) were analyzed by statistics. Results: Eight double-hit lymphomas (DHLs) were identified in all cases, and 45 DELs were selected from 166 remaining cases, which have no significant difference in OS and PFS compared with non-DEL cases (P=0.668 and P=0.790) . Of 42 DEL-cases with follow up data, 24 cases with P53+ or/and BCL2 (S+) are significantly shorter OS and PFS than others (P=0.003 and P=0.000) , in which the cases with P53+/BCL2 (S+) co-expression were the worst prognosis, and P53/BCL2 co-weaker positive DEL cases even have superior OS and PFS than those non-DELs. Although statistics showed that the cases of P53+ or/and BCL2 (S+) have a lower OS and PFS in total cases (P=0.063 and P=0.024) , it is not the case when the DEL-cases take out from total cases, that is the cases with P53+ or/and BCL2 (S+) are as similar OS and PFS as others in non-DEL group (P=0.590 and P=0.550) . Conclusion: The strong expression of P53 and BCL2 proteins can be used as indicators of stratified diagnosis and poor prognosis of DEL.

Prognostic Significance of BCL-2 and BCL-6 Expression in MYC-positive DLBCL

BACKGROUND

Double-expression lymphoma (DEL) is a rare subgroup of diffuse large B-cell lymphoma (DLBCL), which has coexpression of MYC and BCL-2. Coexpression of MYC and BCL-2 is considered a prognostic marker portending poor outcomes. However, the prognostic effect of BCL-2 and BCL-6 expression in DLBCL remains controversial.

MATERIALS AND METHODS

Immunohistochemical staining was performed to detect MYC, BCL-2 and BCL-6 expression in 212 patients with newly diagnosed DLBCL and assess the prognostic effects of BCL-2 and BCL-6 expression. The DLBCL patients were treated with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine [Oncovin], prednisone)-like regimens.

RESULTS

Retrospective analysis revealed that BCL-2⁺ and BCL-2⁺/MYC⁺ were prognostic factors indicative of poor outcomes. Patients with BCL-2⁺ and/or MYC⁺ expression had a poorer prognosis than that of patients with BCL-2^- and/or MYC^- expression. Patients with BCL-2⁺/MYC^- expression showed a trend toward poorer survival than those with BCL-2^-/MYC⁺ expression, suggesting that BCL-2 plays a more important role than MYC. Also, patients with BCL-6^-/MYC⁺ expression had poorer progression-free survival than those with BCL-6⁺/MYC⁺ expression. In addition, patients with BCL-2⁺/MYC⁺/BCL-6^- expression had the worst prognosis, suggesting that BCL-6^- is a prognostic factor for poor outcomes for MYC⁺ DLBCL patients. Altogether, our findings have shown that BCL-2 is an independent prognostic factor and possibly plays a more important role than MYC in MYC⁺ DLBCL patients. Furthermore, we found that BCL-6^- expression could also be a prognostic factor portending poor outcomes for MYC⁺ DLBCL patients.