Identification of MF subgroups using hierarchic clustering methods. (A) Unsupervised clustering analysis of approximately 3400 genes in 53 MF cases revealed 2 main MF clusters. Cluster 2 tends to represent more patients with tumor stage disease and nuclear STAT3 expression, characteristics associated with aggressive disease. (B) Using a T statistic and an adjusted P value, genes significant in the differentiation of MF cluster 1 and MF cluster 2 were identified. After removal of ESTs and hypothetical genes, a total of 334 named genes were found. The expression pattern of these 334 genes is notably different between MF cluster 1 and cluster 2, as shown by unsupervised hierarchic clustering.