Mirdametinib is a highly selective MEK1/2 inhibitor developed for the treatment of neurofibromatosis type 1 (NF1)-associated plexiform neurofibromas.98 These tumors arise due to mutations in the NF1 gene, leading to hyperactivation of the Ras-Raf-MEK-ERK pathway. Here, MAP2K1 is linked to neurofibromatosis type 1.