XPA-210: A new proliferation marker determines locally advanced prostate cancer and is a predictor of biochemical recurrence

Purpose: XPA-210 is a proliferation marker derived from Thymidine kinase-1. It is of clinical significance in kidney, breast, and bladder cancer. There are no data available for XPA-210 in prostate cancer (PC). Herein, we aim to determine the clinical usefulness of XPA-210 in PC. Materials and methods: In a retrospective study, cancer and benign tissue samples of 103 patients (median age 65 years, median PSA 9.04 ng/ml, median Gleason score 6) who underwent prostatectomy were constructed to a tissue micro array and stained for XPA-210. Semi-quantitative results were correlated with pathological and clinical data by Wilcoxon-Kruskall-Wallis and linear regression analysis. Expression levels in PC were correlated between the time of biochemical recurrence and the time to development of metastasis by the Kaplan-Meier method. Multivariate analysis was done to correlate those with the resection status. Results: Mean staining score was 0.51-0.14 for tumor and benign tissue (P < 0.0001). Tumor staining score was significantly associated with Gleason score <6/≥6 (P < 0.0001) and T2/T > 2 (P = 0.0007). When dividing the tumor score by the mean value, higher expression of XPA-210 was associated with a shorter time to biochemical recurrence (P = 0.003) and time to development of metastasis (P = 0.0061). Tumor staining (P = 0.0371) was an independent prognostic factor for biochemical relapse regardless of resection status. Conclusions: XPA-210 is a new tissue-based prognostic marker for prostate cancer histopathology. It reliably differentiates tumor and normal prostatic tissue predicting biochemical relapse and onset of metastatic disease. XPA-210 might be clinically useful for individual decision-making in PC-treatment.