IL21 and diffuse large B-cell lymphoma: Microarray data sets obtained from human transformed germinal centre B cells (BL2) stimulated with CD40L, BAFF, IL21, αIgM F(ab)2 fragments and lipopolysaccharide (LPS) were processed as described previously, combined, and analysed by guided clustering using large-scale gene expression data from 175 DLBCL patients [28, 32].