Low expression of p27(Kip1), a cyclin-dependent kinase inhibitor, is a marker of poor prognosis in synovial sarcoma

BACKGROUND, Low expression of p27(kip1), a dominant cyclin-dependent kinase inhibitor involved in G1-S transition of the cell cycle, recently has been reported to be associated with aggressive tumor growth. It has been shown that active cell proliferation alludes to poor prognosis in patients with s ynovial sarcoma. However, to the authors' knowledge, little is known about the clinicopathologic significance of p27(kip1) in synovial sarcoma. METHODS, p27(kip1) expression was examined immunohistochemically in 55 case s of primary synovial sarcoma, and the relations between p27(kip1) expressi on and several eel proliferation markers, i.e., mitotic index (MI), Ki-67 l abeling index (Ki-67 LI), and clinicopathologic parameters related to poor prognosis, were determined. Univariate and multivariate survival analyses w ere performed to evaluate the prognostic significance of p27(kip1) expressi on in synovial sarcomas. RESULTS, p27(kip1) labeling index (p27(kip1) LI) correlated inversely with MI (r = - 0.44, P = 0.0007) and Ki-67 LI (r = -0.63, P < 0.0001). Of the cl inicopathologic parameters examined, tumor necrosis (P = 0.019) and America n Joint Committee on Cancer (AJCC) stage (P = 0.021) correlated significant ly with p27(kip1) LI. Survival analysis showed that p27(kip1) LI was an ind ependent prognostic factor for overall survival in patients with synovial s arcoma (P = 0.0031). CONCLUSIONS, The study results suggested that low expression of p27(kip1) m ay be useful as a marker of poor-prognosis synovial sarcoma. (C) 2001 Ameri can Cancer Society.