While the paper posted by Al is mainly devoted to renal cancers, I searched if Sorafenib was being investigated for breast cancer.
A brief & probably incomplete search resulted in these finds:
in 2005 a report on a small study involving both ER+ & HER+ patients:
http://www.breastcancersource.com/br...8545_16__.aspx
breast Tyrosine kinase inhibition in advanced cancer
in 2006 the start of a Phase I/II clinical trial for ER+:
http://www.clinicaltrials.gov/ct/show/NCT00217399
Sorafenib and Anastrozole in Treating Postmenopausal Women With Metastatic Breast Cancer
The antiangiogenesis properties of Sorafenib may be one of reasons it may also work with chemo based on this unrelated article which appeared in may 2006:
http://www.sciencemag.org/cgi/conten.../312/5777/1171
Antiangiogenic Therapy: A Universal Chemosensitization Strategy for Cancer? Robert S. Kerbel