Breast cancer, the most common cancer amid women in the majority of countries, is among the most stressful of diseases. The principal effectors of the stress system include the catecholamines epinephrine and norepinephrine. The catecholamines bind to α1-, α2- and β-adrenoceptors (AR). Our group has recently described α2-adrenoceptors in human tumor and non-tumor breast cell lines by reverse transcription (RT)-PCR, immunocytochemistry and binding assays. Moreover, the stimulation by α2-adrenoceptor agonists was associated with increased cell proliferation and tumor growth. On the other hand, we observed a reduction in tumor growth when the animals are treated with the pharmacological α2-antagonist RAUWOLSCINE (RAW). The expression of β2-AR has been described in different experimental models for breast cancer. The aims of the present work were: to assess the effect of β-adrenergic compounds in the human breast cancer cell lines growing in nude mice (IBH-4 and IBH-6); to study the migration potential of these cell lines using video microscopy in three dimensional collagen lattices knowing that migration of tumor cells is a prerequisite for invasion and metastasis development. The daily administration of 1,2mg/kg of the SALBUTAMOL (SALB) significantly diminished tumor growth. The same result was seen when using the α2-antagonist RAW (0,5mg/kg). As an example for tumor IBH-4 treated with SALB, on day 20: 444.16 ± 76.59mm3 vs. 843.40 ± 189.41 mm3, p Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3266.