Oestrogen receptors (ER) and progesterone receptors (PR) are identified in the normal adrenal cortex and tumours and may play a role in tumourigenesis and steroidogenesis (Figure 2).23-25 There are 2 main types of ER: the nuclear ERα and ERβ, and the G protein-coupled ER (GPER). The gene discussed is PGR; the disease is neoplasm.