FGFR1 and lymphoid neoplasm: In 2016, the World Health Organization (WHO) classified EMS as a myeloid/lymphoid neoplasm associated with eosinophilia, and the genes most commonly rearranged in these neoplasm include PDGFRA, PDGFRB, PCM1-JAK2, and FGFR1 (Arber et al. 2016).