Length of CAG repeat at exon 1 of androgen receptor gene is associated to development of bladder carcinoma in males

    LIU Guiª²Qiu, SU Qin, ZHANG Wei, DIAO Xiaoª²Li, FENG Yingª²Ming

    1Department of Pathology, 2Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi¬ðan 710038, China

    ¡¾Abstract¡¿ AIM: To study the possible association between the length of the polymorphic CAG short tandem repeat (STR) at androgen receptor (AR) first exon and bladder cancer development. METHODS: Genomic DNA was extracted from the paraffinª²embedded bladder carcinoma tissues from male patients and amplified by PCR and then the products were resolved by electrophoresis on denaturing polyacrylamide gels and visualized through silver staining. The CAG repeat numbers were assessed by the mobility of their products and direct sequencing for some representative samples. The samples with appendicitis from 94 male patients were examined in a parallel way as a reference group. RESULTS: A total number of 95 of bladder cancer samples were examined. Six of them (6.3%) showed microsatellite instability, with one excluded from the following assessment due to the difficulty in determining precisely the normal position of its amplification product. The CAG repeat numbers for the 94 patients with bladder cancer and the reference patients with appendicitis were 8-26 (20.07¡À3.12) and 14-30 (21.06¡À3.39), respectively, with statistically significant difference. CONCLUSION: CAG STR at the first exon of AR gene is associated to the development and/or progression of bladder carcinoma in male patients. A shorter CAG STR at the locus may predispose the male individuals to the development of bladder cancer. ......