Detection and clinical value of epithelial cellular adhesion molecule (EpCAM) mRNA positive circulating tumor cells in metastatic breast cancer

To test for circulating tumor cells (CTCs) relying on epithelial cellular adhesion molecule (EpCAM) expression in metastatic breast cancer by quantitative real-time reverse transcription-PCR.In the study,47 metastatic breast cancer patients were evaluated by quantitative real-time PCR for detecting EpCAM mRNA. In addition, analyses were carried out for their correlation with patients' clinicopathologic features, response, and the time to progression (TTP).The sensitivity of EpCAM mRNA in the metastatic breast cancer patients was about 40%. However, the specificity of EpCAM mRNA for 20 healthy controls was 100%. TTP was calculated, and compared with that between EpCAM mRNA-positive and EpCAM mRNA-negative groups. For the retrospective study, the median TTP was 7.1 months and 11.1 months (P=0.013) for patients with EpCAM mRNA-positive and EpCAM mRNA-negative, respectively, after the first cycle chemotherapy. Moreover, a statistically significant correlation was demonstrated between EpCAM mRNA and TTP in patients who underwent the first or the second-line chemotherapy (P=0.018), but there was no significance in the patients pretreated with two or more previous chemotherapy lines (P=0.471).This study provides evidence of the presence of EpCAM mRNA in approximately 40% of patients with metastatic breast cancer. There is a strong correlation between EpCAM mRNA results after the first cycle therapy and TTP in metastatic breast cancer patients, and EpCAM mRNA positive after chemotherapy may predict shorter TTP.PubMed02275-804