Objective:To study the expressions of cyclinE

cdk2 and p27kip1 in invasive pituitary adenomas and their relation to clinical biological behaviors. Methods:Western blotting analysis was adopted to detect the expressions of cyclinE

cdk2 and p27kip1 in 37 cases of noninvasive pituitary adenomas and 21 cases of invasive pituitary adenomas. Results:The expressions of cyclinE and cdk2 in invasive pituitary adenomas were significantly higher than those in noninvasive pituitary adenomas(both P<0.01)

but the expression of p27kip1 in invasive group was significantly lower than that in noninvasive group(P<0.01). There were positive correlation between the expressions of cyclinE and cdk2 in pituitary adenomas(P<0.01)

and negative correlation between the former two and p27(both P<0.01);there were positive correlation between the expressions of cyclinE and cdk2 and the invasiveness of pituitary adenomas(both P<0.01)

and negative correlation between the expression of p27 and the invasiveness of pituitary adenomas(P<0.01). Conclusion:The overexpression of cyclinE and cdk2 and the lower expression of p27kip1 were significantly associated with the proliferation

incidence and development of the invasive pituitary adenomas

and cyclinE

cdk2 and p27kip1 proteins may be valuable invasive and prognostic factors for pituitary adenoma.