The t(14;18)-translocation can frequently detected in the peripheral blood and tissue samples from healthy individuals. If the sensitivity of the assay used for the detection is high enough in almost all healthy individuals one or multiple cell clones carrying the t(14;18)-translocation can be found with a frequency of 1-100 rearranged cells in 10(6) normal cells. The frequency of these cells seems to be increased with age and smoking habits measured in pack years. The prevalence in Asian (Japanese) individuals appears to be lower than in Caucasians. It has been postulated that this translocation is a primary event for the subsequent development of a follicular lymphoma.