Pituitary adenomas exhibit a wide range of behaviors. The prediction of 
aggressive or malignant behavior in pituitary adenomas remains challenging; 
however, the utility of biomarkers is rapidly evolving. In this review, we 
discuss potential biomarkers as they relate to aggressive behavior in pituitary 
adenomas. While detailed histological subtyping remains the best independent 
predictor of aggressive behavior in the majority of cases, evidence suggests 
that the additional analyses of FGFR4, MMP, PTTG, Ki-67, p53, and deletions in 
chromosome 11 may contribute to decisions concerning management of aggressive 
pituitary adenomas.