The use of real-time quantitative polymerase chain reaction and comparative genomic hybridization to identify amplification of the REL gene in follicular lymphoma

Using comparative genomic hybridization (CGH), aberrations in DNA copy numb er were studied before and after transformation of follicular lymphoma to d iffuse large B-cell lymphoma in six patients (15 lymph node biopsies in tot al). The most common and also the most discrete and intense amplification o ccurring in four out of 15 biopsies from three different patients was of 2p 13-16. Using real-time quantitative polymerase chain reaction (RQ-PCR), REL amplification was found to be implicated at this locus. This technique als o identified amplified REL in a further two biopsies, presumably below the detection level of CGH. REL amplification was quantified by comparing it, i n most cases, with three endogenous reference genes, albumin, beta (2)-micr oglobulin and CD8 alpha, that lie close to REL on 2p. There was no correlat ion apparent between 2p13-16 amplification or REL amplification and transfo rmation. This study shows the usefulness of coupling CGH, for detecting rec urring abnormalities, with the real-time PCR technique for rapid gene dosag e quantification and confirms that the REL gene is a potential candidate in the pathogenesis of a particular subset of follicular lymphomas.