title: TGF-beta repressors SnoN and Ski are implicated in human colorectal carcinogenesis.
abstract: BACKGROUND
  The TGF-beta signaling repressors SnoN and Ski have been critically implicated in human cancer.
  
  
  METHODS
  To explore the role of SnoN and Ski in the development and progression of colorectal cancer we examined their protein expression profile by immunohistochemistry in a series of human colorectal adenomas, carcinomas and lymph node metastases. The mRNA expression of SnoN was also quantified by Real-Time RT-PCR.
  
  
  RESULTS
  SnoN and Ski were overexpressed both in adenomas with severe dysplasia and colorectal carcinomas. Protein expression was cytoplasmic and nuclear with predominant cytoplasmic localization. The subcellular localization was related differently to pathologic variables of colorectal carcinomas. Although there was no significant association of protein levels with tumor invasion and metastasis, a significant correlation of nuclear SnoN and Ski with beta-catenin pathway was observed. Moreover, SnoN mRNA did not differ in carcinomas as compared to normal control and there was no correlation between SnoN protein and mRNA levels.
  
  
  CONCLUSIONS
  Our findings suggest that SnoN and Ski exert oncogenic effects in human colorectal carcinogenesis and their overexpression is implicated in early stage disease.
authors.affiliation: Clinical Oncology Laboratory, School of Medicine, University of Patras, Rio Patras, Greece.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Bravou
authors.forename: Anna
authors.initials: A
authors.lastname: Antonacopoulou
authors.forename: Helen
authors.initials: H
authors.lastname: Papadaki
authors.forename: Konstantina
authors.initials: K
authors.lastname: Floratou
authors.forename: Michalis
authors.initials: M
authors.lastname: Stavropoulos
authors.forename: Vasso
authors.initials: V
authors.lastname: Episkopou
authors.forename: Chariklia
authors.initials: C
authors.lastname: Petropoulou
authors.forename: Haralabos
authors.initials: H
authors.lastname: Kalofonos
mesh_terms: D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018450:Disease Progression; D015536:Down-Regulation; D015870:Gene Expression; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; C060615:SKIL protein, human; D016212:Transforming Growth Factor beta; C060614:SKI protein, human