ABSTRACT
BACKGROUND: Circulating tumor cells (CTC) are discussed to be an ideal surrogate marker for individualized treatment in metastatic breast cancer (MBC) since metastatic tissue is often difficult to obtain for repeated analysis. We established a nine gene qPCR panel to characterize the heterogeneous CTC population in MBC patients including epithelial CTC, their receptors (EPCAM, ERBB2, ERBB3, EGFR) CTC in Epithelial-Mesenchymal-Transition [(EMT); PIK3CA, AKT2), stem cell-like CTC (ALDH1) as well as resistant CTC (ERCC1, AURKA] to identify individual therapeutic targets. RESULTS: At TP0, at least one marker was detected in 84%, at TP1 in 74% and at TP2 in 79% of the patients, respectively. The expression of ERBB2, ERBB3 and ERCC1 alone or in combination with AURKA was significantly associated with therapy failure. ERBB2 + CTC were only detected in patients not receiving ERBB2 targeted therapies which correlated with no response. Furthermore, patients responding at TP2 had a significantly prolonged overall-survival than patients never responding (p = 0.0090). PATIENTS AND METHODS: 2 × 5 ml blood of 62 MBC patients was collected at the time of disease progression (TP0) and at two clinical staging time points (TP1 and TP2) after 8-12 weeks of chemo-, hormone or antibody therapy for the detection of CTC (AdnaTest EMT-2/StemCell Select™, QIAGEN Hannover GmbH, Germany). After pre-amplification, multiplex qPCR was performed. Establishment was performed using various cancer cell lines. PTPRC (Protein tyrosine phosphatase receptor type C) and GAPDH served as controls. CONCLUSIONS: Monitoring MBC patients using a multimarker qPCR panel for the characterization of CTC might help to treat patients accordingly in the future.
Subject(s)
Biomarkers, Tumor/genetics , Breast Neoplasms/diagnosis , Breast Neoplasms/therapy , Neoplastic Cells, Circulating/metabolism , Palliative Care , Transcriptome , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Case-Control Studies , Cell Line, Tumor , Epithelial-Mesenchymal Transition/genetics , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , MCF-7 Cells , Monitoring, Physiologic/methods , Neoplasm Metastasis , Neoplastic Cells, Circulating/pathology , Real-Time Polymerase Chain Reaction/methods , Treatment OutcomeABSTRACT
PURPOSE: There is increasing interest in circulating tumor cells (CTCs) as a biomarker in bladder cancer (BC). In the present pilot study, we used a platform originally developed for detection of breast cancer CTCs to assess breast cancer-associated transcripts in CTCs of patients with different stages of BC. Moreover, transcripts specific for cancer stem cells and epithelial mesenchymal transition (EMT) were assessed. METHODS: We prospectively enrolled 83 BC patients and 29 controls. The AdnaTest® system was used to enrich epithelial cells in peripheral blood and to detect breast cancer-associated, stem cell-specific or EMT-specific transcripts. Test results were correlated with clinical and pathological stage. RESULTS: A positive AdnaTest® BreastCancerDetect was present in 6.9 % of controls (group A), 6.7, 15.0 and 18.7 % of patients with non-muscle-invasive BC (B), cM0 muscle-invasive BC (C) and metastatic BC (D) (p = 0.13). Stem cell-specific transcripts in group A, B, C and D were detected in 10.3, 10.0, 22.5 and 31.3 % (p = 0.03). EMT-associated transcripts were present in 3.5, 3.3, 15.0 and 18.7 % (p = 0.03). In group C, epithelial and stem-like transcripts correlated with tumor stage (p = 0.01 and 0.04). CONCLUSIONS: CTCs with expression of breast cancer-associated transcripts are present in a considerable proportion of patients with BC. EMT and stem cell-specific transcripts of CTCs correlate with clinical stage and can be detected in patients negative for epithelial transcripts. The prognostic relevance of AdnaTest® results in BC patients and potential implications for therapy decisions remain to be determined in prospective studies.
