Objective: To determine whether eukaryotic elongation factor 1 alpha 2 (eEF1A2), a transforming gene previously shown to be highly expressed in primary human ovarian tumours, is a prognostic marker.
Methods: We have used an antibody specific for eEF1A2 to measure eEF1A2 protein expression in 500 primary ovarian tumours in a tissue microarray. We have also ectopically expressed eEF1A2 in SK-OV-3 cells, a clear cell carcinoma line that does not normally express eEF1A2.
Results: We have shown that eEF1A2 has high expression levels in approximately 30% of all primary ovarian tumours. 50% of serous tumours, 30% of endometrioid, 19% of mucinous and 8% of clear cell tumours highly express eEF1A2. Ectopic expression of eEF1A2 in the SK-OV-3 clear cell carcinoma line enhances their in vitro proliferative capacity and ability to form tumour-like spheroids in hanging drop culture. Expression of eEF1A2 did not alter sensitivity to anoikis, cisplatin, or taxol. In serous cancer, eEF1A2 is an independent prognostic marker for survival and high eEF1A2 protein expression was associated with increased probability of 20-year survival.
Conclusions: eEF1A2 is highly expressed in ovarian carcinomas. Its expression enhances cell growth in vitro, and eEF1A2 expression is likely to be a useful ovarian cancer prognostic factor in ovarian cancer patients with serous tumours.