Novel
biomarkers predicting
prostate cancer (PCa) aggressiveness and
docetaxel therapy response of PCa patients are needed. In this study the correlation between nuclear Eg5-expression, PCa
docetaxel response and PCa aggressiveness was assessed. Immunohistochemical staining for nuclear Eg5 was performed on 117 archival specimens from 110 PCa patients treated with
docetaxel between 2004 and 2012. Samples were histologically categorized as positive/negative. Median follow-up time from diagnosis was 11.6 years. Nuclear Eg5-expression was significantly related to
docetaxel response (p=0.036) in tissues acquired within three years before
docetaxel initiation. Nuclear Eg5-expression was not related to Gleason-score (p=0.994). Survival of patients after
docetaxel initiation did not differ based on nuclear Eg5-expression (p=0.540). Analyzing samples taken before hormonal
therapy, overall survival and time to
docetaxel use were significantly decreased in patients with nuclear Eg5-expressing
tumors (p<0.01). Eg5-positive nuclei were found more frequently in T4-staged
tumors (p=0.04), Gleason 8-10
tumors (p=0.08), and in metastasized
tumors (p<0.01). Multivariate analyses indicated that nuclear Eg5-expression may be an independent parameter for
tumor aggressiveness. Limitations of a retrospective analysis apply. In conclusion, nuclear Eg5-expression may be a predictive
biomarker for
docetaxel response in metastatic castrate-resistant PCa patients and a prognostic
biomarker for
hormone-naive PCa patients. Prospective validation studies are needed.