Fig. 4

Unsupervised clustering reveals similarity among different xenograft tumors. Xenograft lines are stable over multiple transplant generations with respect to gene expression by Affymetrix human transcriptome array. a Unsupervised hierarchical clustering was performed based on gene expression for 87 xenografts derived from 23 unique patients. The dendrogram legend provides individual PDX lines. Xenograft tumors derived from the same patient, regardless of the number of passages, clustered more tightly together than those derived from different patient tumors. The colors indicate different clinical pathological subtypes: pink = TN, dark green = ER-/HER2+, yellow/green = ER+/HER2+, purple = luminal B. “Primary” indicates the subtype of tumor of origin. “PDX” indicates the subtype of individual PDX tumor. Passage number is indicated as black/gray color key. ER, PR, HER2 expression are indicated as expressed (grey) and not expressed (white). b The graph depicts intra and inter sample correlation among multiple generations of xenografts derived from 14 individual tumors from which multiple generations of tumors were available. ER estrogen receptor, HER2 human epidermal growth factor receptor 2, PDX patient-derived xenograft, PR progesterone receptor