Detection of bcl-2/J_H translocation by polymerase chain reaction: A summary of the experience of the Molecular Oncology Survey of the College of American Pathologists

Context. - The t(14;18)(q32;q21) translocation, found in about 85% of follicular lymphomas, brings the bcl-2 gene on 18q21 under control of the immunoglobulin heavy-chain gene transcriptional regulatory elements on 14q32. Detection of this translocation in a clinical sample suspected of containing lymphoma can assist the pathologist in diagnosis and classification of lymphoma. Polymerase chain reaction is a technology that is frequently used to detect the t(14;18)(q32;q21) translocation (bcl-2/J_H). This article reviews the utility of polymerase chain reaction testing for bcl-2/J_H detection and summarizes the experience of participants in the Molecular Oncology Proficiency Survey of the College of American Pathologists from 1997 through 2000. Objective. - To describe current practice and encourage improvement of bcl-2/J_H testing in clinical laboratories. Design. - Retrospective analysis of Molecular Oncology Proficiency Survey data. Participants. - Laboratory participants in the College of American Pathology Molecular Oncology Proficiency Survey. Results. - Twenty-four well-characterized specimens were sent to participants, of which 6 contained bcl-2/J_H major breakpoint region translocations. Eight hundred nineteen major breakpoint region and 323 minor cluster region determinations were performed, with an overall correct response rate of 91% and 94%, respectively. No significant difference in correct response could be found for frozen versus paraffin-embedded tissues. Many laboratories did not know their assay sensitivity. Conclusions. - Overall performance was good; however, there was great variability in the methods reported and lack of knowledge of the limits of detection was common. Continued participation in external quality control programs, such as the Molecular Oncology Survey; dissemination of information that impacts on test performance; and technical recommendations from the molecular diagnostics community are critical for improved testing for bcl-2/J_H.