Immunodetection of androgen and estrogen a,b receptors in human urinary bladder cancer

Abstract

15616 Background: Bladder cancer predominates in males. Loss of androgen receptor (AR) has been associated with invasive and undifferentiated tumors but little is known about the role of hormonal receptors in this type of cancer. Methods: We evaluated samples from 41 nonconsecutive patients treated for bladder transitional cell carcinoma between 2001–2003. Immunohistochemistry was performed using anti-AR and anti-ER a,b antibodies on paraffin-embedded tumors from transurethral resections, nuclear expression was assessed. Western blotting for AR and pAKT were performed in 22 transurethral resections from nonconsecutive bladder cancer patients treated between 2004–2006. Chi-square and U Mann-Witney tests were performed. Results: Immunohistochemistry study: the male/female ratio was 9/1; 61% were noninvasive tumors (pTa, is,1) and 32% were invasive (pT2,3); 22% were G1 and 75% were G2,3. 95% were AR(+), 40% ERa(+) and 94% ERb(+). Significant differences in AR expression were observed between G1 78% and G2,3 tumors 100%, with a high grade tumor prevalence in the AR(+) tumors 81.6% p=0.046. No differences between ERa,b and differentiation were found. G2,3 tumors were predominantly ERb(+). AR was found in 92% noninvasive and in 100% invasive tumors p=0.53. No significant differences were found between invasiveness and ERa,b. Noninvasive tumors showed higher ERa,b expresión (54%, 95% respectively) than invasive tumors (20%, 91% respectively). Western blotting group: 54.5% were primary tumors and 45.5% were recidives. The noninvasive/invasive rate was 59/32%, the G1/G2,3 rate was 4.5/95.5%. 112, 250 and 160 kDa bands were found. AR/pAKT rate was 86.4/100%. 100% of invasive tumors and 86% G2,3 tumors were AR(+). No differences between pAKT, invasiveness, differentiation or AR expression were observed but recidivated tumors had a slight higher median expression level. Conclusions: AR is positively related to tumor grade and might be involved in bladder cancer progression. The profile of AR bands suggest covalent modifications, due to ubiquitin-mediated degradation or to activation mechanisms mediated by SUMO. Nuclear AR and the absence of bands under 90kDa suggest that activated protein is present in bladder cancer. pAKT/AR inhibitors could play a role for bladder cancer therapy. No significant financial relationships to disclose.