PITX2 and fibrosarcoma: Recently, it has been discovered that RGS can interfere with RAS-signaling by binding to the RAS binding domains (RBD) of RAS-effector proteins (such as the rat fibrosarcoma (RAF) isoforms (ARAF, BRAF, and CRAF) and phosphatidylinositol 3-kinase (PI3K)) [18].