Biochemical analyses suggest that truncating PREX2 mutations may have a protumorigenic role (22, 23), although this is confounded by clinical data from TCGA PanCancer dataset, indicating that PREX2 mutation is associated with extended progression-free survival in a curated cohort of cutaneous melanoma, irrespective of BRAF status (Fig. 1C; Supplementary Fig. S1C), but with no improvement in overall survival (Supplementary Fig. S1D and S1E; ref. 7). The gene discussed is BRAF; the disease is cutaneous melanoma.