gms | German Medical Science

Introduction: Docetaxel is recommended the standard therapy in patients with hormone-refractory prostate cancer (HRPCA). Although this regimen for the first time showed a survival benefit for these patients median recurrence free survival is only 6 months. Targeted therapies display an interesting treatment option by inhibition of intracellular signaling pathways or binding of cell growth signals on the cell membrane. The aim of our study was to analyze the expression profile of several molecular markers which are candidates for targeted therapy

Material and Methods: Tumor tissue of 30 patients received from biopsy of metastasis or the prostate were analyzed for the immunhistochemical expression of c-kit, PDGFR, EGFR, VEGF, Her-2/neu and EpCAM. Expression was determined using a semiquantitative score: 0=no staining, 1=1-25% of cells show staining, 2=26-50%, 3=51-75%, 4=76-100%.

Results: 20/30 patients (66%) showed expression of one or more markers. A positive expression of EGFR was found in 40%, c-kit in 24%, PDGFR in 20%, Her-2/neu in 45%, VEGF in 505 and EpCAM in 66% of the patients. A clinical significant expression (i.e. expression scores 3 or 4) of EGFR was found in 20%, of c-kit/PDGFR in13%, of Her-2/neu in 10%, of VEGF in 27% and of EpCAM in 40% of the patients.

Conclusion: The results show that a clinical significant expression of molecular targets is found in about 40% of patients with HRPCA. Based on the expression profile an individual and risk adapted treatment strategy can be applied to each patient. Furthermore the results show that an unselected treatment with targeted therapies will not be successful. Clinical studies are underway to determine the clinical efficacy of the molecular triggered therapy in patients with HRPCA.