BRAF and melanoma: Compared with vemurafenib treatment alone (3 μM), cotreatment with HGF improved viability by > 20% in 10 cell lines, >100% in seven cell lines, and > 200% in three cell lines (Figure 1C), suggesting that HGF may represent a robust and frequent resistance mechanism to BRAF inhibitor therapy in BRAFV600E mutant melanoma.