Prognostic implications of caspase-3 expression in patients with diffuse large B-cell lymphoma (DLBCL)
17500 Background: Caspase-3 activation is an essential step in programmed cell death (apoptosis) and cytotoxic drug-induced apoptosis is mediated by caspase-2 and caspase-3. The following study was designed to evaluate the correlation between Caspase-3 and the clinical outcome in patients with diffuse large B-cell lymphoma. Methods: Caspase-3 was determined by both immunohistochemistry and by quantitative reverse-transcription PCR in 49 previously untreated patients with diffuse large B-cell lymphoma. Results: Caspase-3 was positive in 69.4% of the patients by immunostaining and Tumor cells displayed a diffuse cytosolic expression in 51% of patients. The median value of Caspase-3mRNA within the group by quantitative PCR was 1. Caspase-3mRNA level was μ1 in 28 patients and <1 in 21 patients. Caspase-3 expression was associated with higher tumor stage (P = 0.03), elevated serum lactate dehydrogenase levels (P = 0.02), and the International Prognostic Index (P = 0.0001). Patients with Caspase-3-positive immunostaining had a significantly higher complete response rate to chemotherapy and a longer overall survival than Caspase-3-negative patients. Also, patients with tumor cells expressing diffuse cytosolic immunostaining for caspase-3 had a poor prognosis when compared with those expressing a punctate staining (P > 0.0004 log-rank). A low caspase-3 mRNA expression by quantitative RT-PCR was also associated with a poor prognosis, although this was not statistically significant. In addition, patients with a high TUNEL positivity had a low survival probability (P > 0.02). Conclusions: Our results suggest that Caspase-3 activation or its lack may be a powerful independent predictor of response and survival in previously untreated diffuse large B-cell lymphomas. No significant financial relationships to disclose.