Elevated expression of cyclooxygenase‐2 in breast cancer and ductal carcinoma in situ has no correlation with established prognostic markers

Abstract

Elevated expression of cyclooxygenase-2 (COX-2) has been established to be a feature of breast cancer. There has been inconsistency in the literature regarding the precise significance of this-some studies have found no clinicopathological relevance at all, whilst others have concluded COX-2 expression is an important biomarker in invasive disease and pre-cancerous lesions, correlating with poor prognostic features. We studied COX-2 expression in invasive ductal cancer (IDC) specimens and ductal carcinoma in situ (DCIS) in order to clarify these issues. Archival specimens of IDC and DCIS (n = 39) were stained with a polyclonal antibody to COX-2. Results were correlated with recognised clinicopathological parameters. COX-2 expression occurred in 36.7% of IDCs and 54.5% of DCIS lesions. There was no correlation between increased expression and any clinicopathological features. COX-2 expression did not occur in adjacent non-cancerous tissue (ANCT). We have confirmed that COX-2 expression does occur in invasive cancers, in DCIS, and is not associated with established prognostic markers. The presence of COX-2 expression in DCIS and invasive cancers has positive implications for the future prevention and treatment of breast cancer with COX-2 inhibitors. A large proportion of tumours are, however, COX-2 negative and may be poor candidates for COX-2 suppression.