Human breast cancer invasion signature

ABSTRACT: Introduction: Metastasis of breast cancer is the main cause of death in patients. Previous genome-wide studies have identified gene expression patterns correlated with cancer patient outcome, however these were mostly derived from whole tissue without respect to cell heterogeneity. In reality, only a small subpopulation of migratory and invasive cells inside the primary tumor is responsible for escaping and initiating dissemination and metastasis. When whole tissue is used for molecular profiling, the expression pattern of these cells is masked by the majority of the non-invasive tumor cells. Therefore, little information is available about the crucial early steps of the metastatic cascade: migration, invasion and entry of tumor cells into the systemic circulation. Method: In the past, we have developed an in vivo invasion assay which can capture specifically the highly motile tumor cells in the act of migrating inside living tumors (Wyckoff et al., 2004, Cancer Research). Here, we used this assay in orthotopic xenografts of human MDA-MB-231 breast cancer cells to selectively isolate the invasive cell subpopulation of the primary tumor. We then performed microarray analysis to compare the gene expression profile of these invading tumor cells to the average primary tumor cells. In this way, we derived a gene signature specific to breast cancer migration and invasion in vivo. Each sample of invasive (INV) and average primary tumor cells (APTC) was pooled from two tumor-bearing mice. RNA was extracted, made into cDNA, then amplified with the Clontech SMART amplification kit. Human reference RNA (Clontech) was amplified with identifical protocol. Each sample was then hybridized in a 28K Human cDNA microarray chip, custom printed from Albert Einstein College of Medicine (http://microarray1k.aecom.yu.edu/). Four replicates were used per group (Invasive vs. Average Primary Tumor).

ORGANISM(S): Homo sapiens

SUBMITTER: Patsialou Antonia 

PROVIDER: S-ECPF-GEOD-37733 | biostudies-other |

REPOSITORIES: biostudies-other