Therefore, although the cfDNA technique may be beneficial in the initial screening for the BRAF mutation status (owing to the ease of obtaining a blood sample versus a tumor re-biopsy, and the possibility of loss of the archival sample due to degradation, as seen in two patients in this study), retesting of the archival tumor tissue, if available, should be the primary choice for confirmation of the BRAF mutation status. The gene discussed is BRAF; the disease is neoplasm.