Similarity between corticotropinomas and ectopic ACTH-secreting tumours included their ability to express not only ACTH (or CRH in EAS neoplasms), but also two or more pituitary tropic hormones (GH, PRL, LH, and FSH) and proangiogenic markers (CD31 and VEGF), with equal frequency. The gene discussed is PECAM1; the disease is ACTH-producing pituitary gland adenoma.