Gene expression profiles. (A) Unsupervised, hierarchical clustering of IL-10R lymphoma samples and other lymphoma samples. The dendrogram is based on expression of the most variable genes. Genes whose median expression was above background and whose standard deviation across all samples was >2 in at least 1 lymphoma entity were used for unsupervised hierarchical clustering (n = 3364). Samples from P3-L1, P4-L2, and P5L1 are shown in white and are indicated by arrows. (B) Hierarchical clustering of IL-10R lymphoma samples and activated B-cell–like (ABC) (light pink) and GCB (dark pink) DLBCL samples. Samples from P3-L1, P4-L2, and P5L1 are shown in white and are indicated by arrows. A list of 227 genes used to discriminate between ABC and GCB DLBCL was extracted via a nonparametric test implemented in the LIMMA software package (P < .05). Gene lists were submitted to the Cluster program for calculation of the Pearson correlation coefficient (as a similarity metric) and centroid linkage clustering. The results were visualized with TreeView software. BL, Burkitt’s lymphoma; CB, centroblasts; CC, centrocytes; cHL, classic Hodgkin’s lymphoma; FL, follicular lymphoma; MCL, mantle cell lymphoma; NPLHL, nodular predominance lymphocytic Hodgkin lymphoma; PMBL, primary mediastinal B-cell lymphoma; THRBL, T-cell/histiocyte-rich large B-cell lymphoma; Ton, tonsils.