Tumors were harvested at day 24 post tumor cell engraftment and dissociated into single-cell suspensions. RFP-positive 4T1 cells were isolated by fluorescence-activated cell sorting (FACS). RNA was extracted using the RNeasy Mini Kit. Three independent RNA preparations from cultured 4T1-Luc2-RFP cells and FACS-isolated 4T1-Luc2-RFP cells were submitted for RNA sequencing analysis. Overall design: Primary tumor 4T1-Luc-RFP (n=3) and non-injected 4T1-Luc-RFP (n=3)