title: p27 expression and proliferation in gastrointestinal stromal tumors.
abstract: 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.
authors: Department of Pathology, Akdeniz University Medical School, Antalya, Turkey. tgelen@isbank.net.tr
authors: M Tekinalp
authors: MT
authors: Gelen
authors: G Ozlem
authors: GO
authors: Elpek
authors: N Hikmet
authors: NH
authors: Aksoy
authors: Mehmet
authors: M
authors: Oğüş
authors: Inci
authors: I
authors: Süleymanlar
authors: Fahri
authors: F
authors: Işitan
mesh_terms: 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*
chemical_list: D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; C413374:p27 antigen