Gene expression patterns in FLs.

Gene expression profiles generated from 6 healthy individuals (GC B cells) and 6 patients with relapsed FL were analyzed using cDNA arrays. The mRNA from purified cells were reverse transcribed and hybridized as described in “Materials and methods.” The 6 arrays obtained after hybridization of 6 GC B-cell probes were averaged, as well as 6 arrays from 6 FL-cell probes to create 2 composite arrays, respectively. Finally, after global normalization and subtraction of the background, the 2 composite arrays were compared using the AtlasImage 1.5 software. Genes were selected if ratios were more than 2 or if differences were more than 2000. Positive values indicate that the transcript is more abundant in FL than GC cells and negative values the opposite. Shades of gray indicate expression level of a gene (AU), black bars represent expression level more than 10 000, gray more than 5000, and white more than 2000. Also listed along side the gene names is the GenBank accession number. The genes are grouped according to their function as determined from the literature.