Cytosolic phospholipase A2-α expression in breast cancer is associated with EGFR expression and correlates with an adverse prognosis in luminal tumours.

BACKGROUND: The eicosanoid signalling pathway promotes the progression of malignancies through the production of proliferative prostaglandins (PGs). Cytosolic phospholipase A(2)α (cPLA(2)α) activity provides the substrate for cyclooxygenase-dependent PG release, and we have previously found that cPLA(2)α expression correlated with EGFR/HER2 over-expression in a small number of breast cancer cell lines. METHODS: The importance of differential cPLA(2)α activity in clinical breast cancer was established by relating the expression of cPLA(2)α in tissue samples from breast cancer patients, and two microarray-based gene expression datasets to different clinicopathological and therapeutic parameters. RESULTS: High cPLA(2)α mRNA expression correlated with clinical parameters of poor prognosis, which are characteristic of highly invasive tumours of the HER2-positive and basal-like subtype, including low oestrogen receptor expression and high EGFR expression. High cPLA(2)α expression decreased overall survival in patients with luminal cancers, and correlated with a reduced effect of tamoxifen treatment. The cPLA(2)α expression was an independent predictive parameter of poor response to endocrine therapy in the first 5 years of follow-up. CONCLUSION: This study shows a role of cPLA(2)α in luminal breast cancer progression, in which the enzyme could represent a novel therapeutic target and a predictive marker.