BERKELEY, CA (UroToday.com) - Men have a higher incidence of bladder cancer (BC) than women.
Recent findings have implicated both androgens and androgen receptors (AR) in BC. Animal studies have shown that the incidence of spontaneous and chemically induced bladder tumor development is significantly greater in male than female rats. Resultantly, previous works studied the expression of the AR in human BC. Approximately 50% of BC patients express AR with decreased AR expression associated with advanced stages and high-grade disease. For example, T2 tumors were previously found to have lower AR expression compared to Ta and T1A tumors and AR expression in high-grade disease was lower than low-grade BC. Given these data, authors have concluded that a significant loss of AR expression is associated with aggressive BC, relating AR expression to an aggressiveness feature. However, these results have been gathered on a limited number of patients.
n our study, we analyzed the expression of AR in BC and its correlation with gender, grade, stage and clinical outcome on a large multi-institutional (Toronto/Dallas) cohort. We showed that AR positivity is uncommon in BC and is not gender-related. Actually, only 13% of our BC population showed positivity for AR expression, and no differences were found among high- and low-grade tumors. Moreover, no statistically significant differences were observed between AR expression in men and women. In addition, no statistically significant differences were found between muscle-invasive AR-positive and AR-negative cases in time to death, or time to recurrence. Even using different techniques and antibodies to show immunohistochemical expression, we were unable to replicate previously published results. A possible explanation is that some of previous studies considered ‘faint’ or ‘sporadic’ staining as a positive result. Since immunohistochemistry is sometimes a subjective technique, we attempted to objectify our results by using bright field microscopic imaging for immunohistochemical reading. Even with this objective system, the study remained negative. Due to these discrepancies, further studies are required to elucidate the role of AR and also to explain differences among men and women in relation to BC. At the present time, we believe that AR does not play a major role in BC.
Carmen Mir and Alexandre R. Zlotta as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.