Circulating and disseminated tumor cells: diagnostic tools and therapeutic targets in motion

// Hongxia Wang 1,* , Nikolas H. Stoecklein 2,* , Peter P. Lin 3 and Olivier Gires 4,5 1 Department of Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China 2 Department of General, Visceral and Pediatric Surgery, Medical Faculty, University Hospital of the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany 3 Cytelligen, San Diego, California, USA 4 Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University of Munich, Munich, Germany 5 Clinical Cooperation Group Personalized Radiotherapy of Head and Neck Tumors, Helmholtz, Germany * These authors have contributted equally to this work Correspondence to: Hongxia Wang, email: // Olivier Gires, email: // Keywords : CTCs, DTCs, metastases, EpCAM, MICs Received : April 25, 2016 Accepted : September 20, 2016 Published : September 24, 2016 Abstract Enumeration of circulating tumor cells (CTCs) in peripheral blood with the gold standard CellSearch TM has proven prognostic value for tumor recurrence and progression of metastatic disease. Therefore, the further molecular characterization of isolated CTCs might have clinical relevance as liquid biopsy for therapeutic decision-making and to monitor disease progression. The direct analysis of systemic cancer appears particularly important in view of the known disparity in expression of therapeutic targets as well as epithelial-to-mesenchymal transition (EMT)-based heterogeneity between primary and systemic tumor cells, which all substantially complicate monitoring and therapeutic targeting at present. Since CTCs are the potential precursor cells of metastasis, their in-depth molecular profiling should also provide a useful resource for target discovery. The present review will discuss the use of systemically spread cancer cells as liquid biopsy and focus on potential target antigens.