The 14;18 translocation in European cases of follicular lymphoma: comparison of Southern blotting and the polymerase chain reaction.

The 14;18 chromosomal translocation is widely recognized as a cytogenetic abnormality associated with follicular lymphomas, but estimates of its frequency in this type of lymphoma vary widely from less than 50% to almost 90%. Furthermore, no extensive data have been published on the frequency of t(14;18) in European cases of follicular lymphoma. Lymph nodes from 51 patients with follicular lymphomas obtained from two European centres (Oxford and Copenhagen) were examined for the presence of this translocation. Southern blotting and the polymerase chain reaction (PCR) were used in 26 cases and the PCR alone in 25 cases (from which only degraded DNA or formalin fixed samples were available). DNA probes capable of detecting rearrangement at both the major and the minor breakpoint regions were employed. We could detect t(14;18) in only 21 out of 51 cases (41%). However, a review of the literature showed that comparable results have been obtained previously using both cytogenetic and molecular biological techniques and our results support the view that the global incidence of t(14;18) in follicular lymphoma is no greater than 70%. Furthermore, this study has indicated that the PCR is a reliable method for identifying t(14;18) when only formalin-fixed paraffin-embedded tissue or degraded DNA is available.