The present invention provides, inter alia, methods, pharmaceutical compositions, and kits for treating or ameliorating the effects of a cancer in a subject, which harbors an atypical BRAF mutation (i.e. a non-V600E/K BRAF mutation), comprising an ERK inhibitor. Also provided are methods for identifying a subject having an atypical BRAF mutant cancer who would benefit from therapy comprising an ERK inhibitor.