We then performed immunohistochemistry to examine the expression and localization of FOS and JUN proteins and their phosphorylated forms, which represent their activated state, in adrenal tumors (APAs, CPAs, and non-functioning adrenal incidentalomas), as well as in the corresponding adjacent adrenal cortex and histologically normal adrenal tissue. This evidence concerns the gene FOS and adrenal gland neoplasm.