Peripheral CRF increased tumor growth and neoangiogenesis in vivo. An in vivo model of breast tumor and restraint stress was used and the percentage of tumor bearing mice and the extend of neoangiogenesis were determined as described in Materials and methods. (A) Peripheral administration of antalarmin diminished the stress-induced increase of the percentage of tumor bearing mice. (B) Representative pictures of the histological analysis. (C) The area of vascularization is increased in animals exposed to stress but this effect is abolished by the inhibition of peripheral CRF by the ip administration of antalarmin. ** p < 0.01 compared to control without tumor. # p < 0.05 compared to tumor-bearing mice injected with vehicle. + p < 0.05 compare to tumor-bearing mice exposed to stress and injected with vehicle.