Diagnostic Accuracy of BRAF Immunohistochemistry in Colorectal Cancer: a Meta-Analysis and Diagnostic Test Accuracy Review

The aim of this study was to evaluate the concordance between the BRAF (V600E) mutation test and immunohistochemistry (IHC) and to evaluate the diagnostic accuracy of BRAF IHC for colorectal cancer (CRC) through a systematic review, meta-analysis, and diagnostic test accuracy review. The current study included 1021 CRCs from eight eligible studies. The concordance rates were investigated between BRAF IHC and the mutation test. In addition, diagnostic test accuracy review was conducted and calculated using the value of area under curve (AUC) on the summary receiver operating characteristic (SROC) curve. The positive rate of BRAF IHC was 30.5 % (range; 13.2-66.2 %), and the BRAF mutation was found in 30.2 % (range; 11.7-66.2 %). The overall concordance rate between BRAF IHC and the mutation test was 0.944 (95 % confidence interval (CI) 0.873-0.977). In the BRAF IHC-positive and -negative groups, the concordance rates between BRAF IHC and the mutation test were 0.895 (95 % CI 0.800-0.945) and 0.956 (95 % CI 0.878-0.985), respectively. The pooled sensitivity and specificity were 0.94 (95 % CI 0.91-0.96) and 0.96 (95 % CI 0.95-0.98), respectively. The diagnostic odds ratio was 272.86 (95 % CI 46.11-1614.88), and the value of AUC on SROC curve was 0.9846. Taken together, our results suggest that BRAF IHC is strongly concordant with the BRAF mutation test and has high diagnostic accuracy in BRAF mutation analysis of CRCs. Further cumulative studies on detailed evaluation criteria are needed before application in daily practice.