Expression of EphA2 and EGFR in ovarian cancer cell lines. A. Immunoblot analysis of EphA2 receptor expression in Hey and SK-OV-3 ovarian cancer cell lines. High expression of EphA2 is observed in Hey cells, but no expression is detected in the SK-OV-3 cell line. B. Expression of EGFR is observed in both the Hey and the SK-OV-3 cell lines as shown by immunoblotting. In both cases, β-actin expression was used to demonstrate equal loading of the protein samples so that the relative levels of each receptor could be compared between cell lines.