Circulating tumor cells in prostate cancer (CTC-SCAN)

Circulating tumor cells (CTCs) have been verified as prognostic markers for disease progression in various cancer types. The collaborative project is aimed to validate the number of CTCs isolated from patient`s blood as a prognostic marker for relapse in high-risk prostate cancer patients treated with primary radical prostatectomy or radiotherapy. The partner Peter Sedlmayr (Graz) will add to the collaborative research project in two ways: He will contribute to patient recruitment and sample collection in collaboration with the Dept. of Urology and the Dept. of Therapeutic Radiology and Oncology of the Medical University of Graz. CTC isolation and enumeration will be realized by three different assay formats in comparison. (i) Isolation of CTCs from blood samples using CellSearch as the current "gold standard" for CTC detection, (ii) EPISPOT assay that detects viable CTCs and (iii) GILUPI nanodetector that captures CTCs in vivo. The isolated CTCs will be further characterized by molecular techniques. The numbers of CTCs detected by each assay will be compared to PSA serum levels as the gold standard biomarker in PCA and to clinical outcome to identify the CTC detection assay(s) with the best prognostic value. The systematic approach chosen in this project will validate CTC detection as a novel biomarker for predicting clinical outcome in PCA patients. A validated procedure for CTC detection and characterization will improve risk assessment and contribute to a better stratification of PCA patients to future adjuvant therapies adjusted to the individual risk of each cancer patient. Whereas the samples tested using the CellSearch assay will be sent to the partner laboratory in Hamburg where the instrument for evaluation is located, the EPISPOT test for quantification of CTCs will be performed in Graz. Furthermore the GILUPI nanodetector that captures CTCs in vivo will be applied on patients entering the study in Graz. In addition the Austrian project part specifically aims at characterizing immunocytochemically defined candidate CTCs retrieved from the GILUPI nanodetector. Following single cell lysis and whole genome amplification, array- CGH will be performed, DNA copy number alterations will be determined in comparison to primary tumour tissue and to non-malignant controls.

Due to its frequency and potential lethality, prostate carcinoma is an enormous health problem. Metastases are formed on the basis of dissemination of tumor cells via lymph and blood vessels. Our project dealt with circulating tumor cells (CTCs) in the blood and tried to answer the question whether the concentration of CTCs (determined by three different methods) in the blood of patients with high risk of developing metastases allows for a better determination of prognosis than the prostate-specific antigen (PSA). The patients were treated either by surgery (radical prostatectomy) of by radiotherapy. For this clinical multi- center study we contributed 51 patients who were (with one exception) all treated by irradiation. The other three centers recruited patients who were either treated by surgery (Hamburg) or radiotherapy (Montpellier, Poznan). The question will be answered at the end of a follow-up observation period of 5 years after the treatment of the last patient. Apart from this we compared two different methods of enrichment and counting of these rare cells and found that using a medical wire coated with antibodies binding to the surface of CTCs, which is applied into the arm vein for 30 minutes we detect more CTCs and identify a higher share of patients positive for CTCs than using a conventional method of identification of CTCs in a volume of 7 ml of drawn blood. We developed a method of molecular analysis of CTCs sticking to the wire for the purpose of determination, whether cancer cells have developed resistance to chemotherapy. Furthermore, we evaluated a novel medical wire which has not yet been approved for application in patients that allows for release and subsequent single cells analysis of bound cells. This is of interest as during the course of the disease CTCs may be affected by genomic alterations due to selective pressure under chemotherapy. These alterations may affect the prognosis and the choice of therapy