MAPK9 and urinary bladder cancer: In the present study, using the strategies of gain (overexpression)‐ or loss (knockdown)‐function approaches, we show that overexpressed RhoGDIβ inhibits miR‐200c expression, releasing its binding to the 3′‐UTR region of jnk2 mRNA and promoting JNK2 expression, in turn leading to Sp1 activation and mmp‐2 transcription, as well as promoting human bladder cancer cell invasion.