Bcl-xL Gene Expression Correlated with Lower Apoptotic Cell Numbers and Shorter Progression-Free Survival in PCFCL

The expression of bcl-xL, an antiapoptotic member of the bcl-2 family, has been correlated with poor prognosis in nodal follicular lymphomas (NFLs). So far, it has not been studied in primary cutaneous follicle center lymphomas (PCFCLs), which, compared with NFLs, express less frequently t(14;18)(q32;q21) and bcl-2. Using real-time PCR we measured bcl-xL and bcl-2 gene expression levels in laser-microdissected lymphoma cells of 20 PCFCL frozen sections. Numbers of apoptotic cells labeled by TUNEL assay were negatively correlated with bcl-xL expression levels (r=-0.840, P<0.005). Bcl-xL expression was significantly higher in biopsies of patients who developed relapse or disease progression later compared with patients who did not (P=0.022), and higher levels of bcl-xL gene expression were significantly correlated with shorter progression-free survival (PFS) (P=0.017). None of these features was correlated with bcl-2 gene expression levels. Our findings indicate that bcl-xL overexpression is inversely correlated with PFS in PCFCL. Moreover, the inverse correlation between bcl-xL expression levels and apoptotic cell numbers suggests that bcl-xL, through its antiapoptotic effect, might contribute to tumor cell survival in PCFCL.