title: Disturbed XIAP and XAF1 expression balance is an independent prognostic factor in gastric adenocarcinomas.
abstract: BACKGROUND
  Dysregulation of apoptosis is a key factor in carcinogenesis and tumor progression. X-linked inhibitor of apoptosis (XIAP) is the most potent member of the inhibitor of apoptosis protein (IAP) family, which directly inhibits apoptosis by binding to caspases. Antagonists of XIAP have recently been identified: second mitochondria-derived activator of caspase/direct IAP-binding protein with low PI (Smac/DIABLO) and XIAP-associated factor 1 (XAF1). However, little research has been conducted on the association between gastric cancer survival and the mechanism of apoptosis involving XIAP and its antagonists, Smac/DIABLO and XAF1.
  
  
  METHODS
  XIAP, Smac/DIABLO, and XAF1 expression was analyzed by immunohistochemistry (IHC) in 187 gastric adenocarcinomas. Correlations between XIAP, Smac/DIABLO or XAF1 expression and clinicopathological factors were analyzed. Disease-specific survival after surgery was examined.
  
  
  RESULTS
  Of 187 samples, XIAP was overexpressed in 140, Smac was overexpressed in 117, and XAF1 was overexpressed in 106. Individually, XIAP, Smac, and XAF1 were not significantly associated with disease-specific survival. However, patients showing high expression of XIAP and low expression of XAF1 had significantly poorer survival when compared with other groups (P = 0.024).
  
  
  CONCLUSIONS
  The expression balance of XIAP and XAF1 is an independent prognostic factor in gastric adenocarcinoma.
authors.affiliation: Department of Oncological Science Surgery II, Faculty of Medicine, Oita University, Yufu City, Oita, Japan. shiba@med.oita-u.ac.jp
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Shibata
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Noguchi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Takeno
authors.forename: Helmut E
authors.initials: HE
authors.lastname: Gabbert
authors.forename: Uwe
authors.initials: U
authors.lastname: Ramp
authors.forename: Katsunobu
authors.initials: K
authors.lastname: Kawahara
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000230:Adenocarcinoma / Q000378:metabolism* / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D011379:Prognosis; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D015996:Survival Rate; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism*; D016335:Zinc Fingers
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C412403:DIABLO protein, human; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D009363:Neoplasm Proteins; D051636:X-Linked Inhibitor of Apoptosis Protein; C417551:XAF1 protein, human; C496866:XIAP protein, human