OBJECTIVE: To examine the role of androgen receptor (AR) gene amplification and aneusomy of the X chromosome in the development of antiandrogen-resistant prostate cancer. PATIENTS AND METHODS: Twenty patients with prostate cancer resistant to androgen-deprivation therapy were selected for study. The records of patients with tumours before and after antiandrogen therapy, and with a full clinical follow-up, were retrieved. AR gene amplification and X chromosome copy number were assessed by fluorescence in situ hybridization using a labelled probe at locus Xq11-13 for the AR gene and a labelled alpha-satellite probe for the X chromosome. At least 20 nuclei were scored over three tumour areas by two independent observers. RESULTS: Aneusomy of the X chromosome was reported respectively in seven (35%) and 11 (55%) tumours before and after hormone relapse, the AR gene copy number was increased in seven (35%) and 13 (65%), respectively, and AR gene amplification was detected in one (5%) and three (15%), respectively. Neither increased AR copy number nor AR amplification in primary tumours precluded a biological response to androgen-deprivation therapy. CONCLUSION: The rate of AR gene amplification is too low to be solely responsible for the development of antiandrogen-resistant prostate cancer. Also, the presence of amplified AR and cells aneusomic for the X chromosome in primary tumours that respond to androgen-deprivation therapy suggests that an increase in AR gene copy number does not prevent a tumour from responding to this therapy. Therefore other mechanisms which could cause hormone-refractory prostate cancer must be investigated before it is understood why so many patients relapse with this disease.
OBJECTIVE: To examine the role of androgen receptor (AR) gene amplification and aneusomy of the X chromosome in the development of antiandrogen-resistant prostate cancer. PATIENTS AND METHODS: Twenty patients with prostate cancer resistant to androgen-deprivation therapy were selected for study. The records of patients with tumours before and after antiandrogen therapy, and with a full clinical follow-up, were retrieved. AR gene amplification and X chromosome copy number were assessed by fluorescence in situ hybridization using a labelled probe at locus Xq11-13 for the AR gene and a labelled alpha-satellite probe for the X chromosome. At least 20 nuclei were scored over three tumour areas by two independent observers. RESULTS: Aneusomy of the X chromosome was reported respectively in seven (35%) and 11 (55%) tumours before and after hormone relapse, the AR gene copy number was increased in seven (35%) and 13 (65%), respectively, and AR gene amplification was detected in one (5%) and three (15%), respectively. Neither increased AR copy number nor AR amplification in primary tumours precluded a biological response to androgen-deprivation therapy. CONCLUSION: The rate of AR gene amplification is too low to be solely responsible for the development of antiandrogen-resistant prostate cancer. Also, the presence of amplified AR and cells aneusomic for the X chromosome in primary tumours that respond to androgen-deprivation therapy suggests that an increase in AR gene copy number does not prevent a tumour from responding to this therapy. Therefore other mechanisms which could cause hormone-refractory prostate cancer must be investigated before it is understood why so many patients relapse with this disease.
Authors: Liying Zhang; Saleh Altuwaijri; Fangming Deng; Lishi Chen; Priti Lal; Umeshkumar K Bhanot; Ruslan Korets; Sven Wenske; Hans G Lilja; Chawnshang Chang; Howard I Scher; William L Gerald Journal: Am J Pathol Date: 2009-07-23 Impact factor: 4.307
Authors: R Mukherjee; D H McGuinness; P McCall; M A Underwood; M Seywright; C Orange; J Edwards Journal: Br J Cancer Date: 2011-05-10 Impact factor: 7.640