Open AccessPredictive and prognostic role of serum neopterin and tryptophan breakdown in prostate cancer
Author(s) -
Pichler Renate,
Fritz Josef,
Heidegger Isabel,
Steiner Eberhard,
Culig Zoran,
Klocker Helmut,
Fuchs Dietmar
Publication year - 2017
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/cas.13171
Subject(s) - neopterin , kynurenine , medicine , prostate cancer , hazard ratio , odds ratio , urology , prostatectomy , prostate specific antigen , gastroenterology , prostate biopsy , confidence interval , indoleamine 2,3 dioxygenase , receiver operating characteristic , biopsy , biochemical recurrence , oncology , cancer , tryptophan , biology , biochemistry , amino acid
The γ‐interferon‐induced enzymes indoleamine 2,3‐dioxygenase and GTP ‐cyclohydrolase are key players in tumor immune escape mechanisms. We quantified serum levels of neopterin and tryptophan breakdown (tryptophan, kynurenine, and kynurenine‐to‐tryptophan ratio) in addition to prostate‐specific antigen ( PSA ) in newly diagnosed prostate cancer ( PC a) patients ( n = 100) before radical prostatectomy ( RP ) as well as at time of biochemical recurrence ( BCR ) after RP ( n = 50) in comparison to healthy men ( n = 49). Effects of biomarkers on the risk of PC a diagnosis on transrectal biopsy, worse histopathological characteristics of the RP specimens, and cancer‐specific survival ( CSS ) after BCR were investigated. Neopterin (hazard ratio [ HR ], 2.46; 95% confidence interval [ CI ], 1.08–5.61; P = 0.032) and kynurenine ( HR , 2.93; 95% CI , 1.26–6.79; P = 0.012) levels were univariately associated with CSS . When adjusted for other biomarkers, only neopterin remained an independent predictor of CSS ( HR , 2.56; 95% CI , 1.07–6.12; P = 0.035). Only PSA was associated with an increased risk of PC a diagnosis on biopsy, univariately (odds ratio, 3.14; 95% CI , 1.68–5.88; P < 0.001) as well when adjusted for other biomarkers (odds ratio, 3.29; 95% CI , 1.70–6.35; P < 0.001). Moreover, only preoperative PSA was able to predict positive surgical margin (area under the receiver operating characteristic curve [ AUC ] = 0.71; 95% CI , 0.59–0.82; P = 0.001), higher Gleason score ( AUC = 0.75; 95% CI , 0.66–0.85; P < 0.001) and extraprostatic involvement ( AUC = 0.79; 95% CI , 0.69–0.88; P < 0.001) at RP specimens, respectively. Although serum neopterin and tryptophan breakdown cannot be considered as biomarkers in detecting PC a or in predicting worse final pathological findings, neopterin levels are useful for stratifying patients into different prognostic groups after BCR .