title: Evaluation and identification of factors related toKRASandBRAFgene mutations in colorectal cancer: A meta-analysis.
abstract: OBJECTIVE
  The aim of this meta-analysis is to evaluate the distribution pattern of KRAS and BRAF mutations in colorectal cancer.
  
  
  METHODS
  The database was searched without language restrictions. Meta-analyses were conducted using the STATA software. We calculated the odds ratio (OR) and its 95% confidence interval (95% CI) to estimate the distribution of and correlation between KRAS and BRAF mutations, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) in left- and right-sided colorectal cancer.
  
  
  RESULTS
  The studies were divided into five groups: (1) distribution of KRAS/BRAF mutations in distal and proximal colorectal cancer, the summary OR value was 1.24 versus 4.03, (2) distribution of KRAS/BRAF mutations in CIMP-low/Neg and CIMP-high (CIMP-H) tumors, the summary OR value was 0.77 versus 10.49, (3) distribution of KRAS/BRAF mutations in MSI-low (MSI-L)/microsatellite stable (MSS) and MSI-high (MSI-H) tumors, the summary OR value was 0.51 versus 9.60, (4) proportion of CIMP-H/MSI-H tumors among distal and proximal colorectal tumors, the summary OR value was 3.66 versus 6.54, and (5) proportion of CIMP-H tumors among MSI-L/MSS and MSI-H tumors, the summary OR value was 5.87.
  
  
  CONCLUSIONS
  The meta-analysis reveals that KRAS has a slightly higher mutation rate in MSI-L/MSS tumors. Moreover, BRAF mutations have higher detection rates in right-sided colorectal cancer, which suggests that BRAF mutations are likely in CIMP-H tumors. Therefore, based on these findings, the molecular diagnostic tests to be conducted in colorectal cancer patients can be determined according to the location/clinical features of the tumor.
authors.affiliation: Department of Gastrointestinal Oncology, Affiliated Hospital Cancer Center, Academy of Military Medical Sciences, Beijing, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Pathology, Beijing Friendship Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Guang-Yong
authors.initials: GY
authors.lastname: Chen
authors.affiliation: Department of Pathology, Affiliated Hospital Cancer Center, Academy of Military Medical Sciences, Beijing, People's Republic of China.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Xu
authors.affiliation: Department of Pathology, Affiliated Hospital Cancer Center, Academy of Military Medical Sciences, Beijing, People's Republic of China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Wang
authors.affiliation: Department of Pathology, Affiliated Hospital Cancer Center, Academy of Military Medical Sciences, Beijing, People's Republic of China.
authors.forename: Yong-Fang
authors.initials: YF
authors.lastname: Wu
authors.affiliation: Department of Integrated Chinese Traditional Medicine and Western Medicine, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, People's Republic of China.
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Fang
mesh_terms: D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000235:genetics*; D018899:CpG Islands; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D053842:Microsatellite Instability; D009154:Mutation; D016017:Odds Ratio; D010641:Phenotype; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D017594:Publication Bias; D018631:ras Proteins / Q000235:genetics*
chemical_list: D048493:Proto-Oncogene Proteins B-raf; D018631:ras Proteins