Identification of different gene expression patterns in low and high grade non-Hodgkin's lymphomas by differential...

We have compared the patterns of gene expression in non-Hodgkin's lymphoma (NHL) biopsy samples from patients with either low grade or high grade disease, by the polymerase chain reaction (PCR) based technique of differential display. By using a combination of 30 primer pairs we estimate that we were able to survey over 3,000 genes expressed in these tissues. In this study we compared a group of three low grade follicular centre lymphomas with a group of two high grade diffuse large cell lymphomas and scored only those PCR products that were represented in all samples of each group. In doing so we were able to avoid many of the problems associated with the occurence of false PCR-positives. 139 differences were then scored as representing genes which may be differentially expressed during the transformation from low to high grade disease. However, as many of these might simply reflect changing populations of cells, we focused on only those genes which appeared to be expressed exclusively in either low grade or high grade disease. We have identified 14 such genes, of which 10 were low grade specific and 4 were high grade specific. This approach therefore appears to offer a systematic method for the identification and characterisation of differentially expressed genes, which are characteristic of different NHL sub-types.