Impact of cyclooxygenase-2 over-expression on the prognosis of breast cancer patients

Establishing new predictive and prognostic factors in various cancers is an ongoing challenge for many decades. Biomarkers detected in preclinical studies as predictive and prognostic factors could be potential targets for new drug development. Cyclooxygenase enzyme plays a key role in inflammation and has two isozymes synthesized by cyclooxygenase-1 and cyclooxygenase-2 genes. Cyclooxygenase enzyme was first evaluated in colorectal cancer since its increased synthesis is a known driver for carcinogenesis. Induction of cyclooxygenase-2 gene causes cancer formation by increasing prostaglandin E2 synthesis which results in estrogen production in adipose tissue (1). Besides, prostaglandin E2 shows immunosuppressive effect in the tumor microenvironment promoting tumor progression. Thus, potential role of cyclooxygenase-2 in breast cancer development became the topic of recent studies. Cyclooxygenase-2 gene overexpression was reported in 40-84% of the breast cancer patients depending on the stage of cancer (2). Similarly, cyclooxygenase-2 gene expression increases as the disease progresses from atypical hyperplasia to invasive breast cancer.