RNA-Based CTC Analysis Provides Prognostic Information in Metastatic Breast Cancer.

In metastatic breast cancer (MBC) the molecular characterization of circulating tumor cells (CTCs) provides a unique tool to understand metastasis-biology and therapy-resistance. We evaluated the prognostic significance of gene expression in EpCAM CTCs in 46 MBC patients based on a long follow-up. We selected a panel consisting of stem cell markers (, , ), the mesenchymal marker , receptors (, , , ) and the epithelial marker . Singleplex RT-qPCR was used for and and multiplex RT-qPCR for stem cell markers and receptors. A group of 19 healthy donors (HD) was used as control. Univariate ( = 0.001) and multivariate analysis ( = 0.002) revealed the prognostic value of combined gene expression of (+), , and over-expression for overall survival (OS). The Kaplan-Meier estimates of OS were significantly different in patients positive for ( = 0.028), ( = 0.002), ( = 0.007) and -positive ( = 0.022). Our results indicate that combined gene expression analysis in EpCAM CTCs provides prognostic information in MBC.