Analysis of the polymorphism in the androgen receptor gene of BPH patients

雄激素受体（AR）基因含有一个多态CAG微卫星。先前的研究表明，CAG重复序列的长度与AR的转录活性呈负相关，CAG重复序列的短长度可能与前列腺癌的风险增加有关。本研究的目的是评估增生性腺瘤的生长与AR基因CAG重复长度之间的关系。我们研究了252例行前列腺切除术并经阶梯切片病理诊断为前列腺增生的患者。此外，我们还检查了41名对照（65岁以下），前列腺小于20ml，血清PSA水平正常。前列腺切除术患者CAG重复序列长度与腺瘤重量呈负相关。较大（*64 g：平均+0.8SD）、较小（24 g：平均-0.8SD）腺瘤亚组和对照组的平均重复长度分别为21.7*2.9、2.8*2.2和23.12.4。较大的腺瘤亚组CAG重复长度比较小的腺瘤亚组和对照组短（p<0.05和p<0.02），对于CAG重复数<23的患者，发生较大腺瘤的相对风险有统计学意义（相对风险；2.83.95%置信区间；1.21-6.61）。所有CAG重复数为*17的病例均有较大的腺瘤。综上所述，我们的研究结果提示雄激素受体基因CAG短重复序列可能作为遗传因素之一对前列腺增生的生长具有促进作用。

The androgen receptor (AR) gene contains a polymorphic CAG microsatellite. Previous studies showed that the length of the CAG repeat correlates inversely with transcriptional activity of the AR and the short CAG repeat length might be associated with the increased risk of the prostate cancer. The purpose of the present study was to evaluate an association between the growth of hyperplastic adenoma and the CAG repeat lengths in AR gene.We examined 252 patients who underwent prostatectomy and had the pathological diagnosis of BPH by the step section. Furthermore, we examined 41 controls (>65 year old) with the prostate smaller than 20ml and with normal serum PSA level. CAG repeat length was inversely related to the weight of adenomas in the prostatectomized patients. The mean repeats length for the larger (*64 g : mean+0.8SD), smaller (24 g : mean-0.8SD) adenoma subgroup and the control group were 21.7*2.9 and 2.8*2.2 and 23.12.4, respectively. The larger adenoma subgroup tended to have shorter CAG repeat length than either smaller adenoma subgroup or control group (p<0.05 and p<0.02, respectively), For the patient with <23 CAG repeats, the relative risk developing the larger adenoma was statistically significant (Relative risk ; 2.83.95% confidence interval ; 1.21-6.61). All cases with *17 CAG repeats had the larger adenomas. In summary, our results suggested that short CAG repeats of the androgen receptor gene might have the promoting influence on the growth of the prostatic hyperplasia as one of the genetic factors.