Differential RNA expression of the pS2 gene in the human benign and malignant prostatic tissue

Purpose: The pS2 trefoil protein has been detected in close association wit h neuro-endocrine differentiation in prostate cancer and prostatic intraepi thelial neoplasia. These preliminary results have suggested that pS2 is a c andidate as a specific marker for prostate cancer tissue. To ascertain the specificity of pS2 in prostate cancer tissue, we have used an RT-PCR method from prostate biopsies provided from human malignant and benign prostatic hyperplasia (BPH) tissue. Materials and Methods: Prostate biopsies were obtained from transrectal bio psies from 153 patients with an abnormal DRE or a PSA more than 4 ng./ml. o r symptoms of BPH and a PSA more than 4 ng./ml. Total RNA was extracted fro m fresh frozen specimens of tissue samples. Detection of pS2 transcript com pared with GADPH transcripts was done using RT-PCR. Results: Biopsy results showed that 108 patients had prostate cancer (avera ge Gleason score 6.39 +/- 0.74) and 45 patients had BPH. PS2 RT-PCR results showed that PS2 RNA expression was negative in 83% of the BPH cases. Conve rsely, 92% of prostate cancer specimens were positive (Chi-square: 86.09, p < 0.001). There was no correlation with tumor stage or the Gleason score. Comparing the expression of pS2 in BPH and localized prostate cancer, we fo und a sensitivity of 92% and a specificity of 82%. Conclusions: On this large sample of prostate biopsies from patients at ris k of having prostate cancer, pS2 was demonstrated as an interesting marker significantly associated with prostate cancer. Further work on the expressi on of pS2 according to differentiation and hormonal status is in progress.