Competitive polymerase chain reaction to quantify tumor cells in peripheral blood of patients with t(14;18)-bearing follicular non-Hodgkin's lymphoma: An exploratory study in 8 patients

Abstract

Detection of residual disease in follicular lymphoma is hampered by the observation of t(14;18)-bearing cells in the blood of healthy adult humans. To overcome this problem, we decided to validate a quantification method of t(14;18)-bearing cells and test it in t(14;18)-bearing follicular lymphomas (FL). We designed a competitive PCR method to quantify t(14;18)-bearing cells in peripheral blood. First, we controlled overall reliability (specificity, sensitivity, reproducibility, precision and accuracy); then we used our method to study 16 peripheral blood samples collected in 8 patients with t(14;18)-bearing FL. There were considerable variations in the number of circulating tumor cell (CTC) in FL patients, ranging from zero to 17,813 cells/mL. In 2 patients who were sampled before and after treatment and who attained complete remission (CR), a significant decrease in the number of CTC was observed. In 3 patients with detectable CTC during CR, relapse occurred 4 to 11 months later. Of 3 patients with no detectable CTC, 2 remain in CR 35 and 95 months later, but one relapsed 11 months after sample collection. These preliminary results suggest that quantification of CTC may be worthwhile in follicular lymphoma. It may improve our ability to predict relapse occurrence, but also may help in understanding this peculiar disease.