EPOR and neoplasm: For example, several years of research from multiple laboratories suggested that erythropoietin activates the erythropoietin receptor (EpoR) in tumor cells; a follow-up study, however, showed that only one of the four EpoR antibodies used in these studies detected EpoR and none of the four antibodies were suitable for immunohistochemistry (Elliottet al., 2006).