PDGFRB and esophageal melanoma: Furthermore, in the latter study, involving a series of 10 esophageal melanomas, similar patterns of relatively low mutation burden of five genes involved in the major signaling pathways—consistent with our data—have been documented regarding c-KIT (20%), KRAS (10%), and BRAF (10%), while there was absence of mutations for NRAS and PDGFR genes [40].