Abstract: AIM: To observe the expressions of signal transducer and activator of transcription (STAT)- 6 and prostate-specific antigen(PSA) proteins in prostatic carcinoma, and approach the pathogenesis and early diagnosis methods of prostatic carcinoma. METHODS: All patients were operated during January 2005 to May 2008 including 20 cases of prostatic carcinoma and 36 cases of benign prostatic hyperplasia. The expressions of STAT-6 and PSA proteins were detected by immunohistochemical methods in prostate tissue. The concentration of totall PSA(tPSA) and free PSA(fPSA) in serum were detected by electrochemiluminescence. The prostate volume was measured by color doppler ultrasound. The ratio of f/ t value and prostate specific antigen density (PSAD) were calculated. RESULTS: The expressions of STAT-6 and PSA protein were significantly higher in prostatic carcinoma group (Optical Density: 0.24±0.08 and 0.31±0.09, respectively) than those in benign prostatic hyperplasia group(Optical Density: 0.12±0.06 and 0.20±0.07, respectively) (all P <0.01). The concentrations of tPSA and fPSA in serum and PSAD were significantly higher in prostatic carcinoma group [(43±26) ng/mL, (3.8± 2.2) ng/mL and (0.88±0.66) ng·mL^-1·cm^-3, respectively] than those in benign prostatic hyperplasia group[(6±4) ng/mL, (1.2±0.8) ng/mL and (0.12±0.09) ng·mL^-1 ·cm^-3, respectively] (all P <0.01). There were no statistically differences in the f/t value and prostate volume between prostatic carcinoma group[(0.14±0.10), (61±35) cm³, respectively] and benign prostatic hyperplasia group(0.31± 0.48, 47±24 cm³, respectively) (all P >0.05). CONCLUSION: STAT-6 and PSA may participate in the development of prostatic carcinoma. The concentrations of tPSA and fPSA in serum and PSAD can be applied as effective screening targets for prostatic carcinoma diagnosis.

Key words: prostatic carcinoma, signal transducer and activator of transcription, prostate specific antigen, benign prostatic hyperplasia