Chronic granulocytic leukemia

In 2008, WHO created a new category of myeloid and lymphoid neoplasms with eosinophilia associated with rearrangements of PDGFRA, PDGFRB, or FGFR1; these three target abnormalities are all susceptible to eosinophilia even if they do not have BCR/ABL fusion genes; these three target abnormalities have been shown to be associated with PDGFRA, PDGFRB, or FGFR1. associated with rearrangements of PDGFRA, PDGFRB, or FGFR1";

People with abnormalities in all three targets are sensitive to imatinib therapy even if they do not have the BCR/ABL fusion gene.

CNS Tumors

In the 2021 version of the CNS classification, FGFR1 fusions are seen in extracerebral ventricular neuroblastomas (FGFR1-TACC1 fusion), which can be detected with FGFR1 breakage probes instead.