ERBB4 and ovarian carcinoma: Activation and/or expression of multiple RTK EGFR, ERBB2, ERBB4, MET, and AXL in ovarian cancer cell lines were further validated by immunoblotting with phospho-specific antibodies; As shown in Figure 2A, EGFR, ERBB2, ERBB4, and MET in SKOV3, EGFR, MET, and AXL in OVCA429, and EGFR in ES2 were strongly phosphorylated (Figure 2A).