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