Mutations in the BRAF (B-Raf proto-oncogene serine/threonine kinase) and RAS family genes (KRAS and NRAS) are frequent (e.g., RAS-small G-protein: 15–29% in melanoma, colorectal: 34.1%, lung cancer: 12–30% and BRAF: 50–60 in melanoma; colorectal: 5–20%, lung cancer: 4%), whilst mutations in MEK (MAP kinse-ERK kinase) or ERK (extracellular regulated MAP kinase) are identified less (melanoma 3–8%, colorectal 3%) or rarely, respectively [28]. The gene discussed is RAC2; the disease is lung cancer.