MEK inhibitors may also be efficacious in ECD harboring mutations in MAP2K1; other potential targetable aberrations include programed cell death receptor 1 and mutations in phosphoinositide 3-kinase.
However, at least in the cases of LCH and ECD, there is a very high frequency of activating mutations in MAPK pathway genes, most notably BRAF-V600E, as well as MAP2K1, in LCH and NRAS in ECD.