Evaluation and identification of factors related to KRAS and BRAF gene mutations in colorectal cancer: A meta-analysis

Li Lin¹, Guang-yong Chen², Chun-wei Xu³, Hai-yan Wang³, Yong-Fang Wu³, Mei-yu Fang^4
1 Department of Gastrointestinal Oncology, Affiliated Hospital Cancer Center, Academy of Military Medical Sciences, Beijing, China
² Department of Pathology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
³ Department of Pathology, Affiliated Hospital Cancer Center, Academy of Military Medical Sciences, Beijing, China
⁴ Department of Integrated Chinese Traditional Medicine and Western Medicine, Zhejiang Cancer Hospital, Hangzhou, China

Correspondence Address:
Mei-yu Fang,
Department of Integrated Chinese Traditional Medicine and Western Medicine, Zhejiang Cancer Hospital, No. 38 Guangji Road, Gongshu District, Hangzhou, Zhejiang 310022
China

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-1482.206304

Objective: The aim of this meta-analysis is the distribution pattern of KRAS and BRAF mutations in colorectal cancer (CRC).
Materials and 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 to estimate the distribution of and correlation between KRAS and BRAF mutations, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) in the left- and right-sided CRC.
Results: The studies were divided into five groups: (1) Distribution of KRAS/BRAF mutations in distal and proximal CRCs, the summary OR value was 1.24 versus 4.03, (2) distribution of KRAS/BRAF mutations in CIMP-low/negative 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.
Conclusion: The meta-analysis reveals that KRAS has a slightly higher mutation rate in MSI-L/MSS tumors. Moreover, BRAF mutations have a higher detection rates in the right-sided CRC, which suggests that BRAF mutations are likely in CIMP-H tumors. Therefore, based on these findings, the molecular diagnostic tests to be conducted in CRC patients can be determined according to the location/clinical features of the tumor.

Keywords: BRAF gene, colorectal, CpG island methylator phenotype, KRAS gene, microsatellite instability, mutation, tumor

This has been retracted because it was republished in error due to technical reasons.