p27 expression and proliferation in gastrointestinal stromal tumors.
OBJECTIVE
The p27 is a cyclin-dependent kinase inhibitor which plays a pivotal role in cell proliferation during development and tumorigenesis. Recently, it was shown that low expression of p27 tends to occur in more aggressive neoplasms. In gastrointestinal stromal tumors p27 expression and its correlation with proliferation remain to be elucidated. The aim of the present study was to investigate the expression of p27 and proliferation in gastrointestinal stromal tumors.


METHODS
p27 and Ki-67 immunostained tissue sections from 45 gastrointestinal stromal tumors (benign, borderline and malignant) were subjected to quantitative analysis, and p27 labelling index and Ki-67 labelling index were obtained for each case.


RESULTS
The mean values of Ki-67 labelling index in the three groups were significantly different (benign, 4.53%; borderline, 9.82%; and malignant, 15.35%) (p<0.05). p27 labelling index was decreased in malignant tumors (10.46%) compared with benign (36.56%) and borderline tumors (21.36%) (p<0.05). Moreover, in each group p27 labelling index exhibited a significant inverse relation to p67 labelling index (p<0.001).


CONCLUSIONS
Our results suggest that decreased levels of p27 labelling index could predict the malignant behavior of gastrointestinal stromal tumors and might be associated with tumor cell proliferative activity.
Gelen
M Tekinalp
MT
Department of Pathology, Akdeniz University Medical School, Antalya, Turkey. tgelen@isbank.net.tr
Elpek
G Ozlem
GO
Aksoy
N Hikmet
NH
Oğüş
Mehmet
M
Süleymanlar
Inci
I
Işitan
Fahri
F
D000328:Adult; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005770:Gastrointestinal Neoplasms / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*
D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; C413374:p27 antigen