Simple, inexpensive and precise paraffin tissue microarrays constructed with predrilled ordinary steel embedding moulds

Intratumoral Heterogeneity Determines the Expression of mTOR-pathway Proteins in Prostate Cancer

The aim of this study was to evaluate the expression of mammalian target of rapamycin (mTOR), phosphorylated-mTOR (p-mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in prostate cancer (PCa) in order to assess intratumoral heterogeneity and correlation with clinicopathological parameters. Tissue samples from 115 patients undergoing radical prostatectomy were included in a tissue microarray comprising (A) tissue from the tumor center, (B) malignant border of the tumor, (C) tumor-adjacent benign tissue, and (D) tumor-distant benign prostatic tissue. Immune reactive scores 0-12 were correlated with clinical data in reference to localization. A meta-analysis of studies investigating the association between biochemical recurrence (BCR) and parameters of the mTOR pathway was conducted. Regardless of the location within the tumor, cancer tissue showed higher expression of mTOR, p-mTOR, and 4EB-P1 compared to benign tissue (p < 0.01). Significant differences in expression between tissue samples from groups C and D were observed for mTOR and p-mTOR. When considering expression according to the pathological stage, we observed lower p-mTOR expression in pT3 vs. pT2 (7.9 and 6.3; p = 0.01). After a median follow-up of 74.5 months (IQR 65.0-84.0), 27 patients (23.47%) developed BCR. Weak staining of mTOR was associated with shorter time to BCR (HR: 2.0; p = 0.049) after correcting for PSA and T stage. However, a significant association of mTOR expression with BCR was found for specimens from the malignant border of the tumor (B) but not the tumor center (A) (p = 0.0034 log rank). In a meta-analysis, we found that the expressions of mTOR ((RR) = 0.70; 95% CI 0.43-1.12; p = 0.13) and 4E-BP1 ((RR) = 0.86; p = 0.53) were not statistically associated with BCR, while strong staining of p-mTOR was associated with a lower risk of BCR ((RR) = 0.57; p = 0.002). All 3 markers showed stronger expression in PCa and exhibited local gradients in relation to the border of tumor and healthy tissue. Our results suggest an important role of intratumor heterogeneity for the use of mTOR parameters as biomarkers in PCa.

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.