PIK3CA frequently have gain of function mutations in urothelial cancer. Similar to PI3Ka, PI3Kb is expressed in many different cells, and it is mainly involved in the activation of platelets and development of thrombotic diseases. Studies have shown that PI3Kb contribute to tumor proliferation as well. Specifically, it has an important role in tumorigenesis in PTEN-negative cancers. It's reported that interfering with the gene for PI3Kb might be a therapeutic approach for high-risk bladder cancers with mutant PTEN and E-cadherin loss. Specific isoform inhibitors to PI3Kb is a potential treatment for PTEN-deficient cancers.