Immunohistochemically, all tumors were diffusely positive for CK18 and synaptophysin, while chromogranin A was diffusely expressed in both Cushing syndrome-associated RenNETs and in 3/11 non-functioning RenNETs (Fig. 3A, B). This evidence concerns the gene SYP and Cushing syndrome due to macronodular adrenal hyperplasia.