To evaluate the role of Yap1 in suppression of cellular viability in the bladder cancer cells treated with metformin, first we used RNAi method to knockdown the expression of Yap1 (Fig. 3a) and Yap 5SA mutant plasmid (Fig. 3b) (Mutation of all five serine to alanine at S61A, S109A, S127A, S164A, S381A) to generate a constitutively YAP mutant resistant to phosphorylation by its up-stream kinases. This evidence concerns the gene YAP1 and urinary bladder cancer.