Microfluidic-Based Immunohistochemistry Combined With Next-Generation Sequencing on Diagnostic Tissue Sections for Detection of Tumoral BRAF V600E Mutation

OBJECTIVES Tailored diagnostics requires immunohistochemistry (IHC) and next generation sequencing (NGS). Here we combined on a single paraffin-embedded slide microfluidic-based IHC (micro-IHC) and NGS for BRAF V600E mutation detection in BRAFomas. METHODS For micro-IHC, we performed the primary antibody incubation step of conventional chromogenic IHC in a LabSat device (Lunaphore Technologies SA). Tumor areas immunoreactive for pan-cytokeratin, pan-melanoma, and BRAF V600E mutation-specific antibody were H-scored, microdissected, and analyzed by NGS. RESULTS After 2 minutes, pan-cytokeratin and BRAF micro-IHC increased exponentially (half-time values: 1.7 and 3.2 minutes). Pan-melanoma displayed a higher half-time value of 15 minutes. There was no significant difference in H-score and staining quality, respectively, between conventional and micro-IHC. BRAF V600E mutation was detected in all pan-cytokeratin and pan-melanoma stained samples without amplification but in only 40% of BRAF V600E stained samples with amplification. CONCLUSIONS Micro-IHC enables short antibody incubation times and subsequent NGS. Preprocessing is critical for preservation of DNA quality