Arginase 2, inducible-and endothelial-nitric-oxide synthase (iNOS and eNOS), indoleamine 2,3-dioxygenase (IDO) and TGF-beta, might impair immune functions in prostate cancer (PCA) patients. However, their expression was not comparatively analysed in PCA and benign prostatic hyperplasia (BPH). We evaluated the expression of these genes in PCA and BPH tissues. Seventy-six patients (42 BPH, 34 PCA) were enrolled. Arginase 2, eNOS and iNOS gene expression was similar in BPH and PCA tissues. TGF-beta1 gene expression was higher in BPH than in PCA tissues (p=0.035). IDO gene expression was more frequently detectable (p=0.00007) and quantitatively higher (p=0.00001) in PCA tissues than in BPH. IDO protein, expressed in endothelial cells from both BPH and PCA, was detectable in tumour cells in PCA showing evidence of high specific gene expression. In these patients, IDO gene expression correlated with kynurenine/tryptophan ratio in sera. Thus high expression of IDO gene is specifically detectable in PCA.
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High expression of indoleamine 2,3-dioxygenase gene in prostate cancerChantal FEDER-MENGUS 1 * and Stephen WYLER 1 * , Tvrtko HUDOLIN 2 , Robin RUSZAT 1 , Lukas BUBENDORF 3 , Alberto CHIARUGI 4 , Maria PITTELLI 4 , Walter P. Seventy-six patients, 42 BPH and 34 PCA, were enrolled. Expression of arginase 2, eNOS and iNOS genes was similar in BPH and PCA tissues. TGF-β1 gene expression was significantly higher in BPH than in PCA tissues (p=0.035). In contrast IDO gene expression was more frequently detectable in PCA as compared to BPH (p=0.00007). Its extent was also significantly higher in PCA than in BPH (p=0.00001).Immunohistochemistry revealed IDO protein in endothelial cells from both BPH and PCA. However, in PCA showing evidence of high specific gene expression, IDO was detectable in tumor cells as well. In patients bearing these tumors, IDO gene expression correlated with kynurenine/tryptophan ratio in sera.These data indicate that while genes encoding Arginase 2, iNOS, eNOS and TGF-β immunosuppressive factors are expressed in PCA and BPH, high expression of IDO gene is only detectable in PCA.