Hierarchical cluster analysis of immunohistologic data. The expression patterns of 6 proteins (LMO2, HGAL, CD10, BCL6, MUM1/IRF4 [MUM1], and BCL2) in 143 cases of DLBCL are shown. Positive staining is indicated in red, lack of staining in green, and uninformative data in white. LMO2 protein expression is clustered on the same branch of the dendrogram as germinal-center proteins HGAL, BCL6, and CD10 and away from non–germinal-center proteins MUM1 and BCL2.