Normalized quantitative gene expression analysis of circulating tumor cells in primary and metastatic breast cancer patients – Embedded Tumor Cell Calibrator Technique

Background: The purpose of this study was the validation of a new preanalytical enrichment and molecular detection method using embedded tumor cell calibrators (ETC) for quantitative gene expression analysis of circulating tumor cells (CTC) in breast cancer patients. Methods: The high affinity antibodies BM7 (MUC–1) and VU1D9 (EpCAM) were used for immunomagnetic tumor cell enrichment. Samples from every patient were devided in native probes and matched calibrator probes containing either 2 or 10 breast carcinoma tumor cells (ETC). A real-time quantitative RT-PCR approach was established using primers and FAM-lab…