Expression of cell cycle regulator p27(Kip1) is correlated with survival of patients with astrocytoma

p27(Kip1) is a cyclin-dependent kinase inhibitor that negatively regulates cell proliferation by mediating cell cycle arrest in G(1). This study was u ndertaken to assess the prognostic value of p27(Kip1) for astrocytomas. Tis sue samples from 130 astrocytomas (WHO grade 1, 5 cases; grade 2, 23 cases; grade 3, 64 cases; grade 4, 38 cases), including 92 primary and 38 recurre nt tumors, were examined immunohistochemically for Ki-67 and p27(Kip1) expr ession. Patient charts were reviewed for clinical presentation, and surviva l was followed, The p27(Kip1) labeling index (LI) ranged from 2.3 to 98.4%, with a mean value of 47.5% (+/-23.4%). The p27(Kip1) LI decreased with inc reasing tumor grade but did not correlate with other parameters. There was no correlation between Ki-67 LI and p27(Kip1) LI, For patients with primary astrocytomas, the 50% survival times of those with low p27(Kip1) LI (<50%) and those with high p27(Kip1) LI (greater than or equal to 50%) were 17.1 and 69.6 months, respectively. For patients with high-grade tumors, the 50% survival times were 13.1 months for those with low p27(Kip1) LI and 33.7 m onths for those with high LI, On multivariate analysis, p27(Kip1) was one o f the most significant prognostic factors, indicating that low p27(Kip1) LI was associated with poor prognosis (primary, risk ratio = 2.5, P = 0.0023; high-grade, risk ratio = 2.2; P = 0.0139). The expression of p27(Kip1) was inversely related to tumor grade and positively related to favorable outco me of patients with astrocytoma, suggesting that p27(Kip1) may be a candida te for prognostic factor for this tumor.