Expression of gamma-aminobutyric acid receptor (subtype A) in prostate cancer.

Background: In prostate cancer, gamma-aminobutyric acid (GABA) has been previously reported to increase cellular proliferation via the ionotropic GABAa receptor (GABAar) and to promote cellular invasiveness via the metabotropic GABAb receptor.

Methods: In this study, we have investigated, by immunohistochemistry, GABAar levels in 12 normal human prostate, 13 benign prostatic hyperplasia (BPH) and 148 human prostate cancer specimens. We have also examined the effect of several GABA agonists and antagonists on the in vitro proliferation of four human prostate cancer cell lines: LNCaP, MDA-PCA-2b, DU145 and PC3.