Clinical significance of BRAF V600E mutation in circulating tumor DNA in Chinese patients with melanoma.

The present study aimed to assess the B rapidly accelerated fibrosarcoma (BRAFV600E ) status in plasma from Chinese patients with melanoma, and evaluated its prognostic value following treatment with BRAF inhibitors. Mutation-specific 3D digital polymerase chain reaction (dPCR) was used to quantify BRAFV600E in circulating tumor DNA (ctDNA) in 58 patients with melanoma, prior to treatment with BRAF inhibitors. Correlations between baseline ctDNA levels and clinicopathological characteristics and clinical benefits were then statistically analyzed. The concordance and sensitivity of BRAFV600E between ctDNA and tumor tissue were 70.2% and 76%, respectively, in 58 patients with melanoma. BRAFV600E mutation in ctDNA correlated with lactate dehydrogenase concentration (P=0.04) and Eastern Cooperative Oncology Group score (P=0.04). There was no correlation between BRAFV600E of ctDNA with response, progression-free survival (PFS), or overall survival (OS) following targeted therapy. The objective response rate, PFS and OS stratified by BRAFV600E of ctDNA were 30.0% vs. 56.7%, (P=0.3), 8.1 months vs. 6.7 months, (P=0.38) and 65.6 months vs. 42.3 months (P=0.52), respectively, for undetectable and mutant types. In conclusion, 3D dPCR is appropriate for ctDNA detection and BRAFV600E in ctDNA is a non-invasive biomarker in patients with melanoma.