title: Identification and characterization of CDH1 germline variants in sporadic gastric cancer patients and in individuals at risk of gastric cancer.
abstract: OBJECTIVE
  To screen and characterize germline variants for E-cadherin (CDH1) in non-hereditary gastric cancer (GC) patients and in subjects at risk of GC.
  
  
  METHODS
  59 GCs, 59 first degree relatives (FDRs) of GC, 20 autoimmune metaplastic atrophic gastritis (AMAGs) and 52 blood donors (BDs) were analyzed for CDH1 by direct sequencing, structural modelling and bioinformatics. Functional impact on splicing was assessed for intronic mutations. E-cadherin/β-catenin immunohistochemical staining and E-cadherin mRNA quantification using RT-PCR were performed.
  
  
  RESULTS
  In GCs, 4 missense variants (p.G274S; p.A298T; p.T470I; p.A592T), 1 mutation in the 5'UTR (-71C>G) and 1 mutation in the intronic IVS12 (c.1937-13T>C) region were found. First pathogenic effect of p.A298T mutation was predicted by protein 3D modelling. The novel p.G274S mutation showed a no clear functional significance. Moreover, first, intronic IVS12 (c.1937-13T>C) mutation was demonstrated to lead to an aberrant CDH1 transcript with exon 11 deletion. This mutation was found in 2 GCs and in 1 BD. In FDRs, we identified 4 variants: the polymorphic (p.A592T) and 3 mutations in untranslated regions with unidentified functional role except for the 5'UTR (-54G>C) that had been found to decrease CDH1 transcription. In AMAGs, we detected 2 alterations: 1 missense (p.A592T) and 1 novel variant (IVS1 (c.48+7C>T)) without effect on CDH1 splicing. Several silent and polymorphic substitutions were found in all the groups studied.
  
  
  CONCLUSIONS
  Overall our study improves upon the current characterization of CDH1 mutations and their functional role in GC and in individuals at risk of GC. Mutations found in untranslated regions and data on splicing effects deserve a particular attention like associated with a reduced E-cadherin amount. The utility of CDH1 screening, in addition to the identification of other risk factors, could be useful for the early detection of GC in subjects at risk (i.e. FDRs and AMAGs), and warrants further study.
authors.affiliation: Departement of Translational Research, Centro di Riferimento Oncologico (CRO), National Cancer Institute, Aviano, Pordenone, Italy.
authors.forename: Marica
authors.initials: M
authors.lastname: Garziera
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Canzonieri
authors.forename: Renato
authors.initials: R
authors.lastname: Cannizzaro
authors.forename: Silvano
authors.initials: S
authors.lastname: Geremia
authors.forename: Laura
authors.initials: L
authors.lastname: Caggiari
authors.forename: Mariangela
authors.initials: M
authors.lastname: De Zorzi
authors.forename: Stefania
authors.initials: S
authors.lastname: Maiero
authors.forename: Enrico
authors.initials: E
authors.lastname: Orzes
authors.forename: Tiziana
authors.initials: T
authors.lastname: Perin
authors.forename: Stefania
authors.initials: S
authors.lastname: Zanussi
authors.forename: Paolo
authors.initials: P
authors.lastname: De Paoli
authors.forename: Valli
authors.initials: V
authors.lastname: De Re
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D015703:Antigens, CD; D001483:Base Sequence; D015820:Cadherins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D018095:Germ-Line Mutation; D006801:Humans; D007150:Immunohistochemistry; D007438:Introns / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins; D051176:beta Catenin