| Description |
Background: Apoptosis plays an important role in normal and malignant lymphopoiesis. Therefore signaling pathways participating in this process are intensively investigated to find their crucial molecules suitable for development and application of new antineoplastic agents. Aims: Based on results of our previous studies and literature search, we selected 9 molecules which play an important role in survival of malignant cells to validate their impact for prediction of outcome in DLBCL. Methods and materials: We studied 46 patients with primary DLBCL.The group consisted of 29 men and 27 women with a median age of 59 years (range, 24-79). Advanced stage (III/IV) was observed in 24 cases (52%) and the distribution according to the IPI was as follows: low risk, 20 cases (44%); low/intermediate risk, 12 (26%); high/intermediate risk 9 (19%); and high risk, 5 (11%). All patients were treated with curative intent and, except for one case, an initial treatment started with a CHOP chemotherapy regimen with a median of 6 administrated cycles. Overall response rate was 69% with a complete response (CR) in 31 patients (67%). For subsequent analyses patients were divided into two subgroups: 1. with cured disease (31 cases, 54%; median follow-up 4,3 years), and 2. with fatal course of disease (21 cases, 46%; median follow-up 9 months). Only patients, who died of disease progression were included. Imunohistochemistry was performed on formalin-fixed, paraffin-embedded tissue sections with monoclonal antibodies against: Akt-1, Akt-2, phospho-Akt-Ser-473 and phospho-Akt-Thr-307, Bcl-2, integrin-betaI (CD29), protein kinase C beta I and II (PKC-betaI, PKC-betaII), gama (PKC-gamma), delta (PKC-delta), and Survivin. The expression was considered positive if 5% or more of the tumor cells were stained with the antibody, except for the cases of CD29, Survivin and Bcl-2, where the limits were: 10%, 20% and 40%, respectively. In addition, the expression of PKC isoforms was analyzed by Real-Time-PCR and obtained Ct-values were compared. P-value was based on Gehan-Wilcoxon test or chi-square test and P-values <0,05 were considered significant. The Kaplan-Meier method was used to estimate overall (OS) and progression-free survival (PFS). Results: Tumor cells expression of phospho-Akt-2-Ser-473, Bcl-2, CD29 and Survivin correlated with an inferior OS and PFS and predicted an adverse outcome in patients with DLBCL. Thus, patients with positive expression of phospho-Akt-2-Ser-473 had a median of OS and PFS lower compared to those with negative expression (OS: 45vs11 months, p<0,008; PFS: 37vs10 months, p<0,004). Similar data were obtained for: Survivin (OS: 40vs29 months, p=0,1; PFS: 40vs15 months, p<0,035), Bcl-2 (OS: 45vs12 months, p<0,015; PFS: 30vs6 months, p<0,02), CD29 (OS: 45vs20 months, p<0,04; PFS: 40vs10 months, p<0,025). In the case of PKC-delta higher mRNA expression correlated with unfavourable outcomes (OS: 45vs10 months, p<0,015; PFS: 35vs9 months, p<0,075). The other results were not statistically significant. Conclusions: Our results have shown that expression of Akt-2, Bcl-2, CD29 and Survivin was significantly associated with a poorer clinical outcome in DLBCL patients. Those molecules could be potential targets for therapeutic interventions in DLBCL. Acknowledgment: This project was supported by Internal Grant Agency, Ministry of Health, Czech Republic. No.:NR/8335-3. E-mail:msvoboda@mou.cz
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