Prognostic significance of bcl-xL gene expression and apoptotic cell counts in follicular lymphoma

Abstract

bcl-xL, a member of the Bcl-2 family, exerts an antiapoptotic effect on lymphocytes. To assess its clinical significance in patients with follicular lymphoma, real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of bcl-xL gene expression was investigated in whole lymph node sections and laser-microdissected lymphoma cells of 27 patients. Compared with 10 patients with reactive follicular hyperplasia, the bcl-xL gene was overexpressed in patients with follicular lymphoma at a higher level in microdissected lymphoma cells. The bcl-xL gene level correlated with the number of apoptotic lymphoma cells labeled by terminal deoxytransferase-catalyzed DNA nick-end labeling (TUNEL) assays (r = -0.7736). Clinically, a high bcl-xL level was significantly associated with multiple sites of extranodal involvement (P = .0020), elevated lactate dehydrogenase level (P = .0478), and an International Prognostic Index indicating high risk (P = .0235). Moreover, bcl-xL gene overexpression was linked to short overall survival times (P = .0129). The value of bcl-xL gene expression as a prognostic marker in follicular lymphoma should thus be considered. © 2004 by The American Society of Hematology.