PCNA and Cushing syndrome due to macronodular adrenal hyperplasia: To conquer such difficulties, we conducted a survey of human genome and tumor genetics and identified several useful (potential) markers such as the expression profiles of cyclin E, P27kip1, FHIT, Bax, Fas, FasL, PCNA, hTERT and Ki-67 for types of Cushing's syndrome.