Hierarchical clustering of lymph node samples comparing distinct subtypes of lymphoma. Heatmaps depict A. Multi-class analysis for cases of RL (grey, n = 16), cHL (black, n = 12), DLBCL (yellow, n = 8) and FL (magenta, n = 25); B. cHL (grey, n = 12) versus NHL (black, n = 53) and C. FL (grey, n = 25) versus DLBCL (black, n = 8). The columns represent the samples and rows represent the solicited genes. Each cell within the grid is indicative of the gene expression level for an individual sample with colour used to depict intensity on a graduating red (high) to green (low) scale. See Additional files 2 and 3 for the lists of top 10 and 20 classifier genes distinguishing HL from NHL and FL from DLBCL.