The Eag potassium channel as a new prognostic marker in ovarian cancer

BACKGROUND: Ovarian cancer is the second most common cancer of the female genital tract in the United Kingdom (UK), accounting for 6% of female deaths due to cancer. This cancer is associated with poor survival and there is a need for new treatments in addition to existing chemotherapy to improve survival. Potassium (K(+)) channels have been shown to be overexpressed in various cancers where they appear to play a role in cell proliferation and progression. OBJECTIVES: To determine the expression of the potassium channels Eag and HERG in ovarian cancer tissue and to assess their role in cell proliferation. METHODS: The expression of Eag and HERG potassium channels was examined in an ovarian cancer tissue microarray. Their role in cell proliferation was investigated by blocking voltage-gated potassium channels in an ovarian cancer cell line (SK-OV-3). RESULTS: We show for the first time that high expression of Eag channels in ovarian cancer patients is significantly associated with poor survival (P = 0.016) unlike HERG channel expression where there was no correlation with survival. There was also a significant association of Eag staining with high tumour grade (P = 0.014) and presence of residual disease (P = 0.011). Proliferation of SK-OV-3 cells was significantly (P < 0.001) inhibited after treatment with voltage gated K(+ )channel blockers. CONCLUSION: This novel finding demonstrates a role for Eag as a prognostic marker for survival in patients with ovarian cancer.