Evolution of BCL-2/IgH hybrid gene RNA expression during treatment of T(14;18)-bearing follicular lymphomas

Bcl-2, the gene over-expressed in follicular lymphomas (FL), is able to blo ck chemotherapy-induced apoptosis. consequently, we wondered whether bcl-2/ lgH expression variations during treatment of FL could predict the outcome of patients with t(14;18)-bearing FL. For this purpose, we used a reverse t ranscription polymerase chain reaction (RT-PCR) assay to analyse 180 serial peripheral blood samples (PBS) during 34 treatment phases in 25 patients w ith t(14;18)-bearing FL. in all patients but two, bcl-2/lgH gene expression was demonstrated in pre-treatment samples. During 16 out of the 34 treatme nt phases (47%), bcl-2/lgH expression became negative: all but one were res ponders to chemotherapy. This conversion was transient in six cases. In 18 treatment phases, bcl2/lgH expression remained detectable: eight were clini cally considered as treatment failures, while eight others achieved PR and two achieved CR. We observed a significant correlation between treatment re sponse and RNA PCR results (P = 0.002). Three-year overall survival of pati ents with stable bcl2/lgX-negative conversion was 100% compared to 54% for the remaining patients (P = 0.069); 3-year freedom from progression was res pectively 87.5% and 13% (P = 0.005). These results indicate a correlation b etween bcl-2/lgH expression Variations and both clinical response and outco me. Whether this might predict disease outcome early remains to be confirme d. (C) 1999 Cancer Research Campaign.