Tumorigenesis driven by the BRAF oncoprotein requires secondary mutations that overcome its feedback inhibition of migration and invasion.

mutation occurs in 46% of melanomas and drives high levels of ERK activity and ERK-dependent proliferation. However, is insufficient to drive melanoma in GEMM models, and 82% of human benign nevi harbor mutations. We show here that BRAF inhibits mesenchymal migration by causing feedback inhibition of RAC1 activity.