title: [Prognostic significance of Ki-67 expression in patients undergoing surgical resection for gastrointestinal stromal tumor].
abstract: OBJECTIVE
  Assessment of malignant potential in gastrointestinal stromal tumor (GIST) is still problematic. The maximum tumor diameter and the mitotic index are generally used as an index of malignancy of GISTs. The Ki-67 labeling index has recently been used as an index of cell growth. The aim of this study was to investigate the prognostic value of Ki-67 in GIST.
  
  
  METHODS
  We retrospectively reviewed the medical records of 32 patients with GIST who underwent surgical resection at Inje University Seoul Paik Hospital. We analyzed their Ki-67 expression, histologic finding, and prognosis.
  
  
  RESULTS
  According to the tumor size and mitotic count, 4 patients were classified as very low risk, 9 patients as low risk, 14 patients as intermediate risk and 5 patients as high risk. The average Ki-67 index was 5.56±4.48%. The median follow-up duration was 35.72±29.04 months, and local/distant recurrences were observed in 6 (18.7%) patients. The overall cumulative disease free survival rates in patients with Ki-67 index ≤5% at 1 year, 2 years, and 5 years were 100%, 100%, and 86%, respectively. The overall cumulative disease free survival rates in patients with Ki-67 index >5% were at 1 year, 2 years, and 5 years were 82.1%, 70.3%, and 46.9%, respectively. There was significant relationship between elevated Ki-67 and disease free survival rate (p=0.007).
  
  
  CONCLUSIONS
  Our study suggests that Ki-67 index >5% confers a higher risk of relapse in patients with GIST. Future work should focus on standardization of Ki-67 assessment and specification of its role in making treatment decisions.
authors.affiliation: Department of Internal Medicine, Seoul Paik Hospital, Inje University College of Medicine, 9 Mareunnae-ro, Jung-gu, Seoul 100-032, Korea.
authors.forename: Seong Yeon
authors.initials: SY
authors.lastname: Jeong
authors.forename: Won Wo
authors.initials: WW
authors.lastname: Park
authors.forename: You Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Young Il
authors.initials: YI
authors.lastname: Park
authors.forename: Seung Hyup
authors.initials: SH
authors.lastname: Kim
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Yoon
authors.forename: Jeong Seop
authors.initials: JS
authors.lastname: Moon
authors.forename: Byung Mo
authors.initials: BM
authors.lastname: Lee
authors.forename: Seong Woo
authors.initials: SW
authors.lastname: Hong
authors.forename: Yun Kyung
authors.initials: YK
authors.lastname: Kang
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D019394:Ki-67 Antigen