Expression of miR-23b in cancer is somewhat controversial because it has been found to be either up-regulated and oncogenic in kidney cancer where it caused translational repression of tumor suppressor PTEN gene [13] or down-regulated and a tumor suppressor in prostate cancer where it directly targets Src kinase and Akt oncogenes [14], while our study indicates it is a tumor suppressor in bladder cancer. This evidence concerns the gene PTEN and urinary bladder cancer.