title: β-catenin and K-ras mutations and RASSF1A promoter methylation in Taiwanese colorectal cancer patients.
abstract: OBJECTIVE
  The purpose of this study was to investigate the associations of β-catenin mutations, K-ras mutations, methylations of the RASSF1A promoter, and the survival of Taiwanese colorectal cancer (CRC) subjects who received 5-fluorouracil (5-FU) adjuvant chemotherapy.
  
  
  RESULTS
  The complete coding region of the K-ras gene and exon 3 and exon 4 of the β-catenin gene isolated from tumor tissues and adjacent normal colon tissues from 117 CRC subjects were sequenced, respectively. Methylations in the RASSF1A promoter region were also investigated. Various characteristics of the 117 subjects were recorded and used in the Cox proportional-hazard model analyses. Three missense mutations, one nonsense mutation, and one deletion were identified in the β-catenin gene. A 2 bp deletion was identified in the K-ras gene. We found that the frequencies of mutations in the β-catenin and K-ras genes were less pronounced in Taiwanese CRC subjects as compared with other populations. Methylations in the RASSF1A promoter region were detected in 73.5% (n=86/117) of the subjects, which was higher than in other studies. Methylations in the RASSF1A promoter have no significant effect on hazards for all CRC deaths caused in Taiwanese CRC patients. No interaction between 5-FU adjuvant chemotherapy and methylations of the RASSF1A promoter was observed.
  
  
  CONCLUSIONS
  The mutation frequencies of β-catenin and K-ras genes in Taiwanese CRC patients are very low, which may suggest that they are not the dominant factors for CRC occurrence and prognosis in Taiwanese CRC patients. Methylation of RASSF1A promoter is independent of the prognosis for Taiwanese CRC patients. Taiwanese subjects differ from subjects of other populations with regard to β-catenin, K-ras, and RASSF1A presentations for CRC.
authors.affiliation: Tzu Chi Stem Cells Center, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, Republic of China.
authors.forename: Shee-Ping
authors.initials: SP
authors.lastname: Chen
authors.forename: Chang-Chieh
authors.initials: CC
authors.lastname: Wu
authors.forename: Sung-Ying
authors.initials: SY
authors.lastname: Huang
authors.forename: Jung-Cheng
authors.initials: JC
authors.lastname: Kang
authors.forename: Sheng-Chun
authors.initials: SC
authors.lastname: Chiu
authors.forename: Kuo-Liang
authors.initials: KL
authors.lastname: Yang
authors.forename: Cheng-Yoong
authors.initials: CY
authors.lastname: Pang
mesh_terms: D000368:Aged; D044466:Asian People; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation; D005260:Female; D011905:Genes, ras; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011401:Promoter Regions, Genetic; D013624:Taiwan; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D051176:beta Catenin / Q000235:genetics*
chemical_list: C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins; D051176:beta Catenin