Preliminary Experience on the Use of the Adnatest® System for Detection of Circulating Tumor Cells in Prostate Cancer Patients

Background: The Adnatest (R) system combines immunomagnetic enrichment of epithelial cells with polymerase chain reaction for prostate cancer (PC)-specific transcripts for the detection circulating tumor cells (CTCs). We evaluated the Adnatest (R) in patients with castration-resistant PC receiving docetaxel chemotherapy. Patients and Methods: CTCs were assessed in 16 patients with castration-resistant PC before cycles one and three of chemotherapy. Furthermore, markers of stein cells and epithelial-mesenchymal transition were assessed. Treatment response was assessed by imaging and prostate-specific antigen measurements. Results: Before chemotherapy, 11 patients were Adnatest (R)-positive whereas five patients were Adnatest (R)-positive before cycle three. A positive Adnatest (R) correlated with radiological progression (p=0.02). Rates of disease progression in epidermal growth factor receptor (EGFR)-positive and -negative patients were 100% and 7.7% (p=0.03). Conclusion: In this preliminary study, the Adnatest (R) detected CTCs in a considerable proportion of patients with castration-resistant PC. First data on certain markers (EGFR and aldehyd dehydrogenase 1) encourage future studies investigating transcripts predicting treatment response.