title: Expression and mutation pattern of β-catenin and adenomatous polyposis coli in colorectal cancer patients.
abstract: OBJECTIVE
  β-Catenin and adenomatous polyposis coli (APC) are major components of the Wnt pathway. This study aimed to investigate the expression of β-catenin and APC in tumors and lymph nodes in colorectal cancer (CRC) patients and the mutational spectrum of the genes coding these proteins.
  
  
  METHODS
  Expression of APC and β-catenin was examined in 124 tumors and 41 lymph nodes. Exon 3 of CTNNB1 and the mutation cluster region (MCR) in exon 15 of the APC gene were screened for mutation by PCR-sequencing.
  
  
  RESULTS
  Nuclear/cytoplasmic immunostaining of β-catenin was detected in 58.1 and 48.8% in tumors and lymph nodes, respectively. In tumors, abnormal expression of β-catenin correlated with tumor size and with those in lymph nodes. Membranous β-catenin expression occurred in 41.9 and 14.6% of tumors and lymph nodes, respectively. In tumors, lack of membranous β-catenin correlated with high invasiveness and metastatic potential. Positive immunostaining for APC was observed in 2 and 14% of tumors and lymph nodes, respectively. Overexpression in nucleus/cytoplasm and lack of membranous β-catenin significantly correlated with a reduced overall survival. Among 25 tumors, four harbour mutation in Ser33 and Ser47 and overexpress the β-catenin in the nucleus/cytoplasm. Mutations were identified in the APC gene in 13 tumors and six mutations were novel.
  
  
  CONCLUSIONS
  Positive association between aberrant expression of β-catenin in the nucleus/cytoplasm of tumors and lymph nodes was observed. Nucleus/cytoplasmic accumulation of β-catenin and loss of membranous expression are related to reduced survival and could serve as a candidate prognostic predictor.
authors: Department of Cancer Genetics, Laboratory of Biomass Valorisation and Eukaryotic Protein Expression, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors: Rania
authors: R
authors: Abdelmaksoud-Damak
authors: Department of Cancer Genetics, Laboratory of Biomass Valorisation and Eukaryotic Protein Expression, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors: Imen
authors: I
authors: Miladi-Abdennadher
authors: Department of Cancer Genetics, Laboratory of Biomass Valorisation and Eukaryotic Protein Expression, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors: Mouna
authors: M
authors: Triki
authors: Department of Anatomopathology, Habib Bourguiba Hospital, Sfax, Tunisia.
authors: Abdelmajid
authors: A
authors: Khabir
authors: Department of Anatomopathology, Habib Bourguiba Hospital, Sfax, Tunisia.
authors: Slim
authors: S
authors: Charfi
authors: Department of Anatomopathology, Habib Bourguiba Hospital, Sfax, Tunisia.
authors: Lobna
authors: L
authors: Ayadi
authors: Department of Oncology, Habib Bourguiba Hospital, Sfax, Tunisia.
authors: Mounir
authors: M
authors: Frikha
authors: Department of Anatomopathology, Habib Bourguiba Hospital, Sfax, Tunisia.
authors: Tahia
authors: T
authors: Sellami-Boudawara
authors: Department of Cancer Genetics, Laboratory of Biomass Valorisation and Eukaryotic Protein Expression, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia. Electronic address: raja.gargouri@cbs.rnrt.tn.
authors: Raja
authors: R
authors: Mokdad-Gargouri
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000096:biosynthesis* / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002467:Cell Nucleus / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000235:genetics / Q000401:mortality / Q000473:pathology*; D003593:Cytoplasm / Q000378:metabolism; D005091:Exons; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000473:pathology; D060449:Wnt Signaling Pathway / Q000235:genetics; D051176:beta Catenin / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D025601:Adenomatous Polyposis Coli Protein; C495270:CTNNB1 protein, human; D051176:beta Catenin
keywords: APC; Colorectal carcinoma; Immunohistochemistry; Prognostic markers; β-Catenin