ADRENOCORTICAL NEOPLASMS - ROLE OF PROGNOSTIC MARKERS MIB-1, P53, ANDRB

Differentiation between benign and malignant adrenocortical neoplasms is made using a combination of clinical and pathologic parameters. Des pite these parameters, it is still difficult to predict the biologic p otential of some tumors. Forty adrenocortical lesions, including 10 hy perplasias, 10 adenomas, 12 carcinomas and eight metastatic/recurrent adrenocortical carcinomas were studied for the expression of MiB-1, p5 3, and the retinoblastoma gene product (RE) utilizing immunohistochemi cal techniques. The mean tumor proliferating fraction (TPF), expressed as the number of MiB-1-positive nuclei per 1,000 tumor cells, was 14. 9 in adenomas, 31.5 in hyperplasias, 208.1 in carcinomas and 166.1 in recurrent or metastatic disease. None of the 20 benign lesions had a T PF of > 80, and only one of the 20 malignancies had a TPF of < 80. Nin e of the 20 carcinomas were positive for p53. None of the benign lesio ns were p53 positive. Thirty-nine cases, including benign and malignan t ones, were RE positive, and one was uninterpretable. We conclude tha t prognostic markers can be of great assistance in recognizing adrenoc ortical carcinomas. High TPF (> 80), as measured by staining with MiB- 1, and positive p53 strongly correlate with malignant behavior and the refore may be useful in distinguishing benign from malignant adrenal l esions. Staining for RE does not appear to be a helpful technique.