OBJECTIVETo study the effect of BRG1 and BRM, the catalytic subunits expressed by SWI/SNF, in benign and malignant prostatic tissues and to correlate the BRG1/BRM expression with the development and progression of prostatic cancer.

METHODSThe expression levels of the BRG1 and BRM proteins in benign and malignant prostatic tissues were studied using semi-quantitative immunohisto-chemistry. The results correlated with various clinical and pathologic parameters.

RESULTSThe average immuno-reactive score for BRG1 expression in prostatic cancer tissues was significantly higher than that in benign prostatic tissues (57+/-9.8 and 19+/-4.1, respectively, P = 0.000 17). The difference was more obvious in the high-grade cancer. On the other hand, BRM expression exhibited a heterogeneous pattern. The average immuno-reactive score for BRM expression was lower in cancer tissues than in benign tissues (112+/-17 and 151+/-19, respectively, P = 0.0047). BRG1 and BRM demonstrated a reciprocal expression pattern in benign and malignant tissues. The average immuno-reactive score for BRG1 expression was higher in the cancer cases with a larger tumor volume than in the cases with a smaller tumor volume (P = 0.0112).

CONCLUSIONSThe expression of BRG1 and BRM correlates with the development of prostatic cancer. Increased BRG1 expression may have certain implications in tumor progression.