Analysis of NKX3.1 expression in prostate cancer tissues and correlation with clinicopathologic features

This study aimed to analyze NKX3.1 expression in tissue samples of benign prostate hyperplasia (BPH) and in three different prostate cancer categories. The correlation of NKX3.1 expression with clinical and pathologic features of patients having undergone radical prostatectomy also was investigated. NKX3.1 expression was determined in tissue samples obtained from four different histopathological categories: (1) from patients treated with transurethral prostatectomy for BPH (n = 26), (2) localized prostate cancer patients subjected to radical prostatectomy (n = 38), (3) biopsy samples from prostate cancer patients who were metastatic at the initial admission (n = 10), and (4) tissue samples of prostate cancer patients administered antiandrogens, but who had undergone transurethral prostatectomy for infravesical obstruction (n = 11). Standard immunohistochemical staining was performed using an antiserum raised against recombinant human NKX3.1. Staining was seen in all categories of prostatic tissues. Immunohistochemistry staining scores were lower in prostate cancer patients. The staining scores were significantly higher in patients with BPH compared to metastatic or localized prostate cancer patients. Staining scores of patients with BPH and of those under antiandrogen therapy were similar. No significant correlation was found between NKX3.1 expression and tumor volume, Gleason sum scores, the presence of extraprostatic extension, tumor stage, or serum PSA. NKX3.1 expression is significantly decreased in prostate cancer patients when compared to BPH. However, the decline of NKX3.1 expression was not correlated with prostate cancer progression and was not associated with advanced stage. Thus, NKX3.1 expression is not a clinically valuable prognostic factor.