Inclusion Criteria:

* women with a recent diagnosis of T1 or T2 non-invasive breast cancer by large core needle or excisional biopsy
* confirmation that tissue was processed in methods acceptable to protocol and sufficient tissue remains post-diagnostic analyses to perform research assessments
* reexcision planned within 10 days to 6 weeks from study start
* if on prevention tamoxifen or raloxifene, must have begun administration at least six weeks prior to initial biopsy and continue through reexcision

Exclusion Criteria:

* no hormone replacement therapy within the 90 days prior to biopsy
* if on prevention tamoxifen or raloxifene, must have begun administration at least six weeks prior to initial biopsy and continue through reexcision
* no evidence of metastatic malignancy of any kind
* no history of asthma, allergy ASA, NSAIDS, celecoxib or other COX-2 inhibitors for a chronic non-oncological condition with the excision of low dose ASA (160 mg daily) during 4 weeks prior to biopsy and for the duration of the study.
* no celecoxib or rofecoxib use within one month of biopsy
* no history of gastrointestinal ulcer or ulcerative colitis requiring treatment
* no current anticoagulants
* no neoadjuvant antihormone or chemotherapy as treatment following biopsy prior to study entry or concurrently with participation on study
* no aromatase inhibitor in the six months prior to participation
* no concomitant lithium
* no known significant bleeding disorder