Clustering of different lymphoid malignancies and normal tissues by hierarchical clustering. Enriched GO biologic process for each gene clusters are indicated on the left. The top T cell–associated cluster of genes are overexpressed in MALT and normal and malignant T cells, but not other B-cell tumors or normal lung. Genes of interest anchoring these gene expression profiles are indicated on the right. The colored bar below the heatmap represents the different tissue types, and the legend key is just below. On the heatmap, red represented up-regulated genes and green down-regulated genes, with the scale represented at the bottom of the figure. The gene expression profiling datasets for normal lung, plasma cells and lymphocytes, and lymphoid neoplasms other than MALT lymphoma were obtained from previously published, publicly available sources as described in “Other gene expression datasets.”