ERBB3 and ovarian cancer: These ovarian cancer cell lines are of low (OVCAR4), moderate (PEO4), and high (SKOV3) HER2 expression status [34], in addition to having variable expression levels of HER3, the key dimerization partner of HER2 in the order PEO4>OVCAR4>SKOV3 [34]., We found that at least part of mechanism of action of the HER2 targeted immunotherapeutic agents involved generation of ROS, which contributed to the killing effects and cancer growth retardation.