An example of unsupervised clustering of microarray analysis of normal lymphoid tissues, cell lines and lymphoid malignancies.

The dendrogram on the left is an enlargement of the one on top of the expression data matrix. Note that the dendrogram cluster cases according to their similarity of gene expression pattern and the CLL, FL and DLBCL cases are largely in three clusters. Also note the expression data matrix with the red and green color indicating over and under expressed genes respectively compared with the standard RNA pool. Figure reprinted with permission from Nature (Nature 403:503-511,2000)