Down-regulated genes of selected categories in HL cell lines.

Down-regulated B-cell–lineage genes (rows) identified by supervised clustering of HL cell lines versus normal B-cell subsets (columns) are represented as matrices and ranked according to the statistical significance (ζ-score). Color changes within a row indicate expression levels relative to the average of the sample population. Values are quantified by the scale bar that visualizes the difference in the ζ-score (expression difference/SD) relative to the mean (Klein et al21). Genes are ranked based on the ζ-score (mean expression difference of the respective gene between phenotype and control group/SD). Genes also identified in the SAGE analysis are marked by S in brackets (asterisk indicates genes identified with a difference of 2:0). The genes are divided in B-cell–, lymphocyte-, or hematopoietic-specific according to their expression. IgG is listed as an example for multiple Ig genes that showed down-regulation. Some genes such as c-Src and Syk are mentioned in the hematopoietic class of genes, despite more ubiquitous expression, because of their well-known functional importance in B-cell signaling. For some genes (eg, TTF, TOSO,Staf50, SIT) limited information of expression is available; therefore the assignment of these genes to the expression classes may be preliminary. T-cell receptor β (TCR-β) germ line transcripts are known to be expressed in tonsillar B cells.55 The complete list of differentially expressed genes is available as supplemental data on theBlood website; see the Supplemental Tables link at the top of the online article.