RAC1 and bladder transitional cell carcinoma: Namely, AP-2γ may enhance EMT through increased Transforming Growth Factor Beta Receptor 1 (TGFBR1) expression which induces p21(RAC1)-Activated Kinase 1 (PAK1) phosphorylation and subsequent Mitogen-Activated Protein Kinase (MAPK) signaling (62) – this is meaningful for BLCA since PAK1 has been related to metastasis and invasion of bladder cancer (71) and MAPK network is itself important in this tumor (72).