Comparison of the Clinical Efficacy of Droplet Digital Polymerase Chain Reaction and Immunohistochemistry for the Detection of BRAF-V600E Mutation in Colorectal Cancer

Abstract

Background: The use of disease screening is limited in colorectal cancer (CRC) because of its unique location, and CRC patients are usually in advanced stages at the time of diagnosis. B-Raf proto-oncogene (BRAF)-V600E mutation is observed in tumors, and BRAF-V600E-mutant metastatic CRC is an aggressive subgroup. Droplet digital polymerase chain reaction (ddPCR) is a specific method for detecting circulating tumor DNA (ctDNA) mutations. This study used BRAF detection on cancer tissue as a standard for verifying the accuracy and heterogeneity of ddPCR in the plasma of CRC patients. Methods: A total of 147 CRC patients were recruited and their clinical data were obtained. Plasma samples were collected from patients to determine cell-free DNA (cfDNA) concentration and ddPCR, and cancer tissues were used for immunohistochemistry (IHC) assay. The effect of BRAF-V600E on patient prognosis was analyzed by Kaplan-Meier curve. Results: cfDNA was markedly increased in patients with CRC metastasis and was positively correlated with the size of non-metastatic tumors. The patients with BRAF-V600E mutation had a lower 5-year survival rate than those without the mutation, suggesting that BRAF-V600E mutation is a potential target for CRC humoral biopsy. Overall, there were some significant differences concerning the detection rates of IHC and ddPCR and the main distribution of ddPCR in multi-detected cases and stage III cases (p < 0.001). Conclusion: This study shows the feasibility of using ddPCR to detect BRAF-V600E in the plasma of CRC patients and the differences between ddPCR and IHC, providing support for the establishment of a CRC detection technique.