PCNA and adrenal cortex adenoma: When the expression of FHIT is negative or weakly-positive but both of Ki-67 and PCNA are strongly positive, adrenocortical carcinoma is suggested; when FHIT is strongly positive but both of Ki-67 and PCNA are negative, adrenocortical hyperplasia is suggested; while when FHIT, Ki-67 and PCNA are all positive, adrenocortical adenoma is suggested.