Interesting but might be limited to women who have not yet acquired herceptin resistance since 800 mg of celecoxib a day and herceptin failed to work in a phase II study involving women who were herceptin resistant.
See:
http://www.ncbi.nlm.nih.gov/entrez/q..._uids=15217939
There seems to be a disagreement in the studies of breast cancer samples over whether HER2 and Cox-2 are closely related but even if HER2 is only as likely to be Cox-2 as breast cancer in general it would still be a substantially big percentage.