To Örebro University

Background: Simply applicable biomarkers for prostate cancer (PCa) predicting the clinical course are urgently needed. Recently, TRIM24 has been identified to promote androgen-receptor signaling and to correlate with poor outcome. Based on these data, we validated TRIM24 as a prognostic biomarker for PCa.

Design: We performed TRIM24 immunohistochemistry on two independent cohorts including a total of 806 primary tumors, 26 locally advanced/recurrent tumors, 30 lymph node metastases, 30 distant metastases and 129 benign prostatic samples from 497 patients. Expression data were correlated with clinic-pathological data including biochemical recurrence free survival (bRFS) as endpoint.

Results: Benign samples show no/low TRIM24 expression in 94%, while tumors demonstrate significantly higher levels. Strongest expression is observed in metastatic tumors. In multivariate analyses, TRIM24 up-regulation correlates with shorter bRFS independent of other prognostic parameters. 5-(10-) year bRFS rates for TRIM24 negative, low, medium and high expressing tumors are 93.1(93.1)%, 75.4(68.5)%, 54.9(47.5)% and 43.1(32.3)%, respectively. Of interest, tumors diagnosed as indolent disease, TRIM24 expression stratifies patients into specific risk groups. Increased TRIM24 expression associates with higher Grade Group, positive nodal status and extraprostatic tumor growth.

Conclusions: Using two large independent cohorts, we found that TRIM24 expression predicts patients’ risk to develop disease recurrence with high accuracy and independently from other established prognostic markers. To our knowledge, TRIM24 is the first prognostic biomarker to be independent, accurate and reproducible on three different primary PCa cohorts. Thus, we strongly suggest introducing TRIM24 in clinical routine as a simple immunohistochemical test.