Skin toxicity of any grade occurred in 68 of 69 patients (99%) with RAS WT tumours, 71 of 74 patients (96%) with RAS MT tumours, 59 of 60 patients (98%) with RAS WT/BRAF WT tumours and 80 of 83 patients (96%) with RAS or BRAF MT tumours. The gene discussed is BRAF; the disease is neoplasm.