Cyclooxygenase-2 (COX-2) is frequently over-expressed in primary breast cancer. There is evidence that COX-2 inhibition exerts anti-tumor effects in breast cancer. To further determine the effect of COX-2 inhibition in primary breast cancer, we aimed at studying the changes in breast cancer tissues of patients treated with the selective COX-2 inhibitor celecoxib.

In a single-centre double-blinded phase II study, breast cancer patients were randomised to receive either pre-operative celecoxib (400 mg) or placebo twice daily for two to three weeks. We collected fresh-frozen pre-surgical biopsies (before treatment) and surgical excision specimens (after treatment) to assess the tumor changes by use a cDNA microarray, which allows to study the genome-wide changes at the transcriptional level.

Inclusion Criteria:

• Female patients suspected of having invasive breast cancer, >1 cm in diameter, and in whom there is an indication for a core or incision biopsy
• Age <75 years at time of diagnosis
• Patient willing and able to comply with the study prescriptions
• Patient able to give written informed consent before patient registration/randomisation
• Pre- and post-menopausal patients are eligible
• Hormone receptor positive and negative patients are eligible
• A negative pregnancy test in pre-menopausal women

Exclusion Criteria:

• HIV, HBV or HCV positivity
• Known hypersensitivity to NSAIDs
• A history of upper gastro-intestinal bleeding
• Endoscopically proven upper gastro-intestinal ulceration
• Patients using NSAIDs, including salicyclic acid
• Systemic use of corticosteroids
• A history or the presence of any other malignancy excepting adequately treated squamous cell skin cancer or in situ carcinoma of the cervix
• Patients who have been treated with neo-adjuvant chemotherapy or hormone therapy