MAP2K7 and embryonal rhabdomyosarcoma: Since dysregulation of the Ras pathway is preferentially associated with ERMS and is responsible for the constitutive activation of MEK/ERK pathways, we included RH30, a rhabdomyosarcoma cell line that is negative for Ras mutations [29], to study the efficacy of MEK/ERK inhibition in cells lacking the constitutive activation of Ras/MEK/ERK pathways.