Clinical quantitation of diagnostic and predictive gene expression levels in follicular and diffuse large B-cell...

Recent microarray gene expression profiling studies have identified gene signatures predictive of outcome, so-called "indicator" genes, for diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). However, measurement of these genes in routine practice remains difficult. We applied real-time polymerase chain reaction (PCR) to polyA cDNAs prepared from 106 archived human frozen lymph nodes (63 of FL, 25 of DLBCL, 10 reactive lymph nodes, and cases with paired samples of FL [4] and subsequent DLBCL [4]). Reverse transcription and polyA reverse transcriptase (RT)-PCR was performed, and resultant cDNA was probed by real-time PCR for 36 candidate indicator genes, selected from microarray studies. Nine genes showed statistically significant different expression between FL and DLBCL, including cyclin B, COL3A1, NPM3, H731, PRKCB1, OVGL, ZFPC150, HLA-DQ-a, and XPB. Of these, cyclin B, NPM3, and COL3A1 were higher in DLBCL. Six genes showed statistically significant higher expression in the neoplastic nodes compared with reactive nodes, namely PRKCB1, BCL-6, EAR2, ZFX, cyclin B, YY1. High levels of YY.1 were associated with a shorter survival interval in both FL and DLBCL. The method is simple, sensitive, and robust, facilitating routine use and may be used as a platform for clinical measurement of prognostic gene signatures.