title: Methylation of protocadherin 10, a novel tumor suppressor, is associated with poor prognosis in patients with gastric cancer.
abstract: OBJECTIVE
  By using methylation-sensitive representational difference analysis, we identified protocadherin 10 (PCDH10), a gene that encodes a protocadherin and is silenced in a tumor-specific manner. We analyzed its epigenetic inactivation, biological effects, and prognostic significance in gastric cancer.
  
  
  METHODS
  Methylation status was evaluated by combined bisulfite restriction analysis and bisulfite sequencing. The effects of PCDH10 re-expression were determined in growth, apoptosis, proliferation, and invasion assays. PCDH10 target genes were identified by complementary DNA microarray analysis.
  
  
  RESULTS
  PCDH10 was silenced or down-regulated in 94% (16 of 17) of gastric cancer cell lines; expression levels were restored by exposure to demethylating agents. Re-expression of PCDH10 in MKN45 gastric cancer cells reduced colony formation in vitro and tumor growth in mice; it also inhibited cell proliferation (P < .01), induced cell apoptosis (P < .001), and repressed cell invasion (P < .05), up-regulating the pro-apoptosis genes Fas, Caspase 8, Jun, and CDKN1A; the antiproliferation gene FGFR; and the anti-invasion gene HTATIP2. PCDH10 methylation was detected in 82% (85 of 104) of gastric tumors compared with 37% (38 of 104) of paired nontumor tissues (P < .0001). In the latter, PCDH10 methylation was higher in precancerous lesions (27 of 45; 60%) than in chronic gastritis samples (11 of 59; 19%) (P < .0001). After a median follow-up period of 16.8 months, multivariate analysis revealed that patients with PCDH10 methylation in adjacent nontumor areas had a significant decrease in overall survival. Kaplan-Meier survival curves showed that PCDH10 methylation was associated significantly with shortened survival in stage I-III gastric cancer patients.
  
  
  CONCLUSIONS
  PCDH10 is a gastric tumor suppressor; its methylation at early stages of gastric carcinogenesis is an independent prognostic factor.
authors.affiliation: Institute of Digestive Disease and Department of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong. junyu@cuhk.edu.hk
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.forename: Yuen Y
authors.initials: YY
authors.lastname: Cheng
authors.forename: Qian
authors.initials: Q
authors.lastname: Tao
authors.forename: Kin F
authors.initials: KF
authors.lastname: Cheung
authors.forename: Cleo N Y
authors.initials: CN
authors.lastname: Lam
authors.forename: Hua
authors.initials: H
authors.lastname: Geng
authors.forename: Lin-Wei
authors.initials: LW
authors.lastname: Tian
authors.forename: Ying P
authors.initials: YP
authors.lastname: Wong
authors.forename: Joanna H M
authors.initials: JH
authors.lastname: Tong
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Ying
authors.forename: Hongchuan
authors.initials: H
authors.lastname: Jin
authors.forename: Ka F
authors.initials: KF
authors.lastname: To
authors.forename: Francis K L
authors.initials: FK
authors.lastname: Chan
authors.forename: Joseph J Y
authors.initials: JJ
authors.lastname: Sung
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D014408:Biomarkers, Tumor / Q000378:metabolism; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism*; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D019175:DNA Methylation / Q000502:physiology*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011230:Precancerous Conditions / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D011379:Prognosis; D000091363:Protocadherins; D013270:Stomach / Q000473:pathology / Q000503:physiopathology; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000378:metabolism; D014183:Transplantation, Heterologous
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; C438603:PCDH10 protein, human; D000091363:Protocadherins