Abstract
Background: The olfactory receptor gene (OR) superfamily is the largest in the human genome. ORs are expressed not only in the neurons of the olfactory epithelium but also in various other tissues in which their functions are largely unknown. We investigated the association between OR51T1 expression in bladder cancer and its malignant potential. Methods: We immunohistochemically examined the expression of OR51T1 in a set of tissue microarray consisting of bladder cancer specimens from 154 patients. We also assessed the effect of OR51T1 silencing via siRNA transfection on the viability of bladder cancer cells. Results: Low levels of OR51T1 expression were detected in 93 (60.4%) bladder cancer cases, whereas 61 (39.6%) showed high levels of OR51T1 expression. OR51T1 expression was significantly elevated in higher grade tumors (p < 0.001). However, there were no significant associations of OR51T1 expression with other clinicopathological features, such as sex, age, and pathological T stage. In a bladder cancer cell line, OR51T1 silencing resulted in significant inhibition in cell proliferation. Conclusions: OR51T1 expression in bladder cancer was found to be associated with higher grade or cell proliferation. These findings suggest the involvement of OR51T1 in bladder cancer progression.