Localisation of a novel region of recurrent amplification in, follicular lymphoma to an similar to 6.8 Mb region of 13q32-33

Follicular lymphoma (FL) is characterised by the presence of the t(14;18)(q 32,q21) and represents similar to 25% of new cases, of non-Hodgkin's lympho ma. While the t(14,18) is a welf-documenterl rearrangement, the role of sec ondary cytogenetic abnormalities in the development and progression of thes e tumours remains unclear. Comparative genomic hybridisation was used to ch aracterise changes in DNA copy number in tumour DNA from patients with this malignancy. The, mean numbers of deletion and amplification events found i n each of the 45 samples studied were 1.8 and 23, respectively. Regions of recurrent (> 10% tumour samples) gain involved chromosomes 2p 13-16 (16%), 7 (20%), 12 (16%), 13q21-33 (18%), 18 (27%), and X (36%) and frequent losse s localised to 6q (29%) and 17p (20%). Amplification of chromosome 13 repre sents a novel finding in FL The minimal amplified region was refined to a 6 .8-Mb interval of 13q32-33 between the BAC clones 88K16 and 44H20 by fluore scence in situ hybridisation studies using metaphase chromosomes derived fr om tumour material. There are a number of reports in the literature suggest ing that amplification of chromosome 13 also occurs in other human cancers. The, location of the putative oncogene on 13q described here In follicular and transformed lymphoma may also be important in the evolution of many ot her malignancies. (C) 2001 Wiley-Liss, Inc.