Many drugs have been designed to target the RTK (receptor tyrosine kinase)- RAS (rat sarcoma)- RAF (rapidly accelerated fibrosarcoma)-MEK (mitogen-activated protein kinase)-ERK (extracellular-signal-regulated protein kinase) pathway, such as RTK inhibitors, BRAF (B-Raf proto-oncogene) inhibitors, and MEK inhibitors. This evidence concerns the gene BRAF and fibrosarcoma.