Gene expression signature of circulating tumor cells (CTC) in patients with colorectal carcinoma (CRC)

15061 Background: Accurate CTC detection may potentially serve as a diagnostic, prognostic and therapeutic cancer marker. Currently, CTC are identified using epithelial markers but some of these markers are also present in circulating hematopoetic cells of healthy individuals and down-regulated in CTC. The objective of this study is to define a CTC gene expression signature that exhibits high detection specificity and sensitivity for CRC patients. Methods: In a prospective two-center study, blood samples were collected from 12 CRC patients (4 stage II, 8 stage IV), 2 stage IV esophageal cancer (EC) patients, 7 breast cancer (BC) patients (1 stage I, 1 stage II, 3 stage III, 2 stage IV) and 6 healthy donors. A viable cell isolation system that utilizes the invasiveness of tumor cells to a cell adhesion matrix was used to enrich CTC. The enriched samples were examined for gene expression profiling (GEP) using the Affymetrix microarray Hu133A chip. Using GEP bioinformatics, 1874 genes differentially expresse...