Project description:To follow the earliest transcriptional changes in pre-metastatic tissues, we orthotopically injected 4T1 cells into the mammary fat pad of female nude mice. Control mice were orthotopically injected with PBS. 7 days post tumor engraftment, the mice were sacrificed and thoroughly perfused with ice cold PBS, and lung and liver samples were flash frozen in liquid nitrogen. Following RNA extraction, the lung and liver RNA samples were analyzed on MOE430A2 Affymetrix arrays using R/Bioconductor software. Expression array was performed on lung or liver tissue from control or tumor-bearing mice. Lung and liver tissues were isolated from 3 control mice (injected with PBS) and 3 tumor-bearing mice (injected with 4T1 cells) 7 days post injection.