Ki-67 labeling index and expression of p53 are non-predictive for invasiveness and tumor size in functional and nonfunctional pituitary adenomas.

Invasive character of pituitary adenomas is neither correlated with increased Ki-67 LI nor with increased p53 expression. Proliferation parameters are independent from adenoma size at initial presentation. The partly elevated expression of Ki-67 in recurrent tumors underlines the clinical importance of the marker.