CAG polymorphic repeat lengths in androgen receptor gene among Japanese prostate cancer patients: Potential predictor of prognosis after endocrine therapy

BACKGROUND. Several investigators have examined the clinical significance of the length of the CAG repeat at the N-terminal region of the androgen receptor in the pathogenesis of prostate cancer. Because the clinical significance of CAG repeat length during the course of prostate cancer in Japanese patients is unknown, the present study analyzed CAG repeat length in relation to several potential clinical factors. MATERIALS AND METHODS. A total of 88 Japanese patients with prostate cancer and a control group of 53 patients with benign prostatic disease were enrolled in this study. The length of the CAG repeat was determined by PCR sequencing and analyzed in relation to several clinical factors. RESULTS. The length of the CAG repeat did not significantly differ between prostate cancer and benign prostatic disease. Although not statistically different with regard to clinical stage and serum PSA level, the CAG repeat length was associated with histological grade and age at diagnosis. In addition, the CAG repeat length in CR and in non CR patients significantly differed at 22.1 +/- 2.4 and 24.4 +/- 3.0, respectively (P = 0.0264), suggesting that the CAG repeat length can act as a molecular marker with which to predict response to endocrine therapy in stage D prostate cancer patients. CONCLUSIONS. A shorter CAG repeat length appears to predict a response to endocrine therapy, showing a positive prognostic value and indicating good prognosis in the metastatic stage of prostate cancer patients. (C) 2002 Wiley-Liss, Inc.