In contrast with what is observed in established control melanoma cells (Supplementary Fig. 6b,d), NRAS/CRAF complexes were strikingly much less abundant than NRAS/BRAF complexes in melanocytes at P10 (Supplementary Fig. 6a,c), thus explaining why CRAF can compensate for BRAF absence in melanoma cells but not in early melanocytic lesions. The gene discussed is RAF1; the disease is melanoma.