Preliminary data indicate a high prevalence of EPH-A4 and a lower expression of EPH-A2 in neuroendocrine neoplasms.72 The expression of EPH-A4, -A5, -B2 and -B5 were evaluated in 18 PTs (seven somatotropic and two corticotropic adenomas, eight nonfunctioning macro-adenomas and one resistant prolactinoma) by immunohistochemistry.41 The data reported, for the first time, the increased expression of mainly EPH-A4 and, to a lesser extent, EPH-A5, -B2 and -B4 in pituitary lesions. This evidence concerns the gene EPHA2 and prolactin-producing pituitary gland adenoma.