Circulating tumor cells: Multimarker gene profile for tailoring chemotherapeutical response in adeno carcinomas.

Abstract

10638 Background: In this experimental work we present a new immunomagnetic technique by the introduction of 2 antibodies (BM7 and VU1D9) for tumor cell selection and the use of a multimarker panel for identification of circulating tumor cells in peripheral blood of patients with adenocarcinomas. Methods: The high affinity antibodies BM7 (MUC1) and VU1D9 (EpCAM) were used for immunomagnetic tumor cell enrichment from 10mL samples of peripheral EDTA-blood of metastatic breast cancer patients and local advanced or/and metastatic gastrointestinal cancer patients. Separated cells were lysed and used for mRNA isolation and c-DNA synthesis. A real-time quantitative RT-PCR approach for the markers cytokeratin 19 and 20 (CK19 and CK20), mammaglobin 1 (MG1), CEA, epithelial cell adhesion molecule (EpCAM), aldehyde dehydrogenase 1 (ALDH1), Survivin, HER-2, immunosupressive CD276, chemokine receptor 4 (CXCR4), hypoxia inducible factor (HIF-1alpha) and metastasis associated in colon cancer (MACC) were used for tumor cell identification. Results: Sensitivity of the marker panel was validated in calibration tests with 2 cells and 10 cultured tumor cells and specificity was confirmed by examination of blood from healthy donors. Positivity rate of local advanced and/or metastatic gastrointestinal cancer patients was 73.5%, while 67.7% of metastatic breast cancer patients showed multimarker positivity. The marker with the highest expression level in metastatic breast cancer patients was CK19 followed by EpCAM. In local advanced and/or metastatic gastrointestinal cancer patients the most frequent identified genes were EpCAM, Survivin and CEA. Patients responding to therapy were characterized by immediate erradication of circulating tumor cells. Conclusions: The optimized surrogate marker panel linked to apoptosis, invasion, angiogenesis and stem cell phenotype should improve early detection of metastasis as well as monitoring of therapy response and selection of tailored therapy regimes. Circulating tumor cells expressing the newly introduced markers Sur, MACC and HIF-1alpha are clearly associated with aggressive tumor behaviour and poor clinical outcome. No significant financial relationships to disclose.