Indoleamine 2,3‐dioxygenase expression is correlated to prognosis in localized prostate cancer.

Abstract

BackgroundIndoleamine 2,3‐dioxygenase (IDO) is an enzyme that acts as an immunomodulatory molecule. It is found in several cancer types where it seems to be associated with tumor escape due to its immunosuppressive mechanisms. Some studies have reported a correlation between carcinogenesis and changes in IDO expression. However, the role of IDO expression in prostate cancer (PC) is unclear. The aim of our study was to evaluate the expression of IDO in localized PC, and to correlate its expression with the classic prognostic factor and recurrence after surgical treatment.MethodsFor this case‐control study, we retrospectively evaluated surgical specimens from 111 patients with localized PC, who underwent radical prostatectomy. Recurrence was defined as a prostate specific antigen (PSA) level exceeding 0.2 ng/ml postoperatively, and the median follow‐up was 123 months. IDO expression was evaluated by immunohistochemistry in 72 cases of which 42 (58%) had biochemical recurrence.ResultsWe found that lower IDO expression was associated with higher Gleason score (p = 0.022) and PSA levels (p = 0.042). The multivariate analyses revealed that the loss of IDO expression and higher PSA levels were independently associated with biochemical recurrence. The chance of recurrence was increased by 85% in patients with lower IDO expression (OR = 0.15; p = 0.009 CI 95% [0.038–0.633]) and increased by 5.5 times in patients with higher PSA levels (OR = 5.51; p = 0.012 CI 95% [1.435–21.21]). The recurrence‐free survival curve also demonstrates that lower IDO expression (p = 0.0004) was associated with lower time to biochemical recurrence.ConclusionThe loss of IDO expression was associated with increased chance of biochemical recurrence, higher PSA, and a Gleason score in localized PC.Support or Funding InformationThe study was supported by São Paulo Research Foundation (FAPESP)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.