Fig. 2.

Sample- and gene-centric expression analyses show that metastasized samples more closely resemble their primary sites than their biopsy site. Legend applies to both plots. (A) Breast tumors that metastasized to the lung, brain, and bone (GSE14107) still appear to be more closely related to other breast samples (red shaded region) than to their metastasis sites when placed in the transcriptomic landscape of 3,030 other expression samples. (B) Recomputing the PCs using only the 164 genes of the breast gene set, as opposed to all 20,252 genes, recapitulates the proximity of the metastasized breast cancer samples to breast tissue samples (orange shaded region), and shows that they lie within the confines of the other breast cancer samples in the database.