[Expression of androgen receptor protein in hormone refractory prostate cancer]

It was reported that androgen receptor (AR) gene amplification was found in hormone refractory prostate (HRPC) and it has been thought to be a possible molecular mechanism for the treatment failure. In this article, the expression of AR protein before and after hormone therapy was examined quantitatively in order to further clarify the relationship between AR expression and the genesis of HRPC.

AR protein content was determined using radioligand binding assay before and after hormone therapy in 28 patients with advanced prostate cancer.

The average levels of AR protein before and after hormone therapy were 390.0 +/- 204.1 fmol/mg protein and 690.4 +/- 444.0 fmol/mg protein, respectively (P < 0.001). In 10 patients whose diseases recurred in 12 months after therapy, the mean levels of AR protein before and after therapy were 398.2 +/- 199.5 fmol/mg protein and 448.2 +/- 274.1 fmol/mg protein, respectively (P > 0.20). In other 18 patients with response duration more than 12 months, the mean levels of AR protein before and after therapy were 386.4 +/- 212.3 fmol/mg protein and 824.9 +/- 468.6 fmol/mg protein, respectively (P < 0.001).

The elevation of AR protein level was most likely to occur in the prostatic tumors that had good response to hormone therapy and might be involved in the genesis of HRPC.