BMC Cancer 2008, 8:270 http://www.biomedcentral.com/1471-2407/8/270 FPriginucripeal1components analysis (PCA) and unsupervised hierarchical clustering into distinct mammary-tumor phenotypes Principal components analysis (PCA) and unsupervised hierarchical clustering into distinct mammary-tumor phenotypes. Mammary carcinoma and adenocarcinoma tumors were developed in transgenic mice expressing the forced activated Stat5 (STAT5ca) or truncated Stat5 (STAT5Δ750). PCA (A) and unsupervised hierarchical clustering (standard corre- lation, B) were performed on genes that were expressed at significantly (P < 0.05) different levels between phenotypes and confirmed the distinction of the two phenotypes. Page 5 of 19 (page number not for citation purposes)