Expression of cyclooxygenase-1 and-2 in human breast cancer

Purpose. We investigated the expression of cyclooxygenase (Cox-1 and Cox-2) in mammary tissues from patients with breast cancer. Methods. We used reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. Results. The cancer cells showed very weak expression of Cox-1, but strong expression of immunoreactive Cox-2. In contrast, immunoreactive Cox-2 was very weak in all of the benign mammary tumors examined, including fibroadenoma (FA) and mastopathy (MP). Immunoreactive Cox-1 was also very weak in these benign tumors. The extent and intensity of immunoreactive Cox-2 polypeptides was significantly greater in the cancer cells than in the FA cells or MP cells. RT-PCR analysis showed enhanced expression of Cox-2, but not Cox-1 in breast cancer tissue, and faint expression of Cox-2 in benign tissue. Conclusions. These results demonstrated that human breast cancer cells generated Cox-2, indicating that Cox-2 might play an important role in the proliferation of breast cancer cells.