Expression data from highly purified MMTV-Neu Tumor Initiating Cells (TICs) and the non-TIC CD24- fraction

The cancer stem cell model maintains that tumors are organized in a hierarchy driven by tumor initiating cells (TICs), and that patient survival inversely correlates with TIC gene expression. Here we generated a prognostic signature for HER2+ breast cancer from TICs purified from MMTV-Her2/Neu mammary tumors. TICs from this model, identified as Lin-:CD24+:JAG1- at a frequency of 2-5% by serial and single cell transplantation assays, showed elevated expression of proliferation genes and low expression of differentiation genes (compared to non-TIC fraction CD24- of the same tumor). We used microarrays to detect differentially expressed genes in the TIC fraction compared to the non-TIC fraction of the same tumor Cells from each primary tumor were separated by FACS into TIC and non-TIC fractions and total RNA was extracted and hybridized on Affymetrix microarrays.