p27 (KIP1)

p27 is a cyclin-dependent kinase inhibitor leading to cell cycle arrest in the G1 phase.

Immunohistochemical expression

Loss or reduction in expression has been associated with poor outcome in carcinomas4,5 of the breast1, prostate3, gastrointestinal tract and lung2. There is increased p27 expression in benign and malignant gastrointestinal endocrine tumours7, with a report of increased expression in well differentiated tumours but loss of expression in poorly differentiated endocrine tumours6. Paradoxically, there is increased expression in small cell carcinoma of the lung, contrasting with the reduced expression in non-small cell carcinoma of the lung8.


Diagnostic utility


1 Chiarle R, Pagano M,Inghirami G The cyclin dependent kinase inhibitor p27 and its prognostic role in breast cancer. Breast Cancer Res 2001; 3:91-4

2 Esposito V, Baldi A, De Luca A, et al. Prognostic role of the cyclin-dependent kinase inhibitor p27 in non-small cell lung cancer. Cancer Res 1997; 57:3381-5

3 1. Fernandez PL, Hernandez L, Farre X, et al. Alterations of cell cycle-regulatory genes in prostate cancer. Pathobiology 2002; 70:1-10

4 Sandhu C,Slingerland J Deregulation of the cell cycle in cancer. Cancer Detect Prev 2000; 24:107-18

5 Tsihlias J, Kapusta L,Slingerland J The prognostic significance of altered cyclin-dependent kinase inhibitors in human cancer. Annu Rev Med 1999; 50:401-23

6 Canavese G, Azzoni C, Pizzi S, et al. p27: a potential main inhibitor of cell proliferation in digestive endocrine tumors but not a marker of benign behavior. Hum Pathol 2001; 32:1094-101

7 1. Guo SS, Wu X, Shimoide AT, et al. Anomalous overexpression of p27(Kip1) in sporadic pancreatic endocrine tumors. J Surg Res 2001; 96:284-8

8 Masuda A, Osada H, Yatabe Y, et al. Protective function of p27(KIP1) against apoptosis in small cell lung cancer cells in unfavorable microenvironments. Am J Pathol 2001; 158:87-96

This page last revised 27.6.2005.

©SMUHT/PW Bishop