Mulliken and Folkman's classification of vascular anomalies defined by G protein abnormalities.9 Vascular malformation results from lack of rap1 effectors, leading to constitutive rhoA/ROCK activation. Normal vessels have high levels of rap1/integrin/VE-cadherin activation, leading to lack of vascular permeability. Hemangiomas demonstrate constitutive rac activation, and thus can be treated by agents that inhibit rac/reactive oxygen signaling.
