FIP1L1-PDGFRA is a relatively infrequent but treatment-relevant mutation in primary eosinophilia that is indicative of an underlying systemic mastocytosis.
CD25 therefore appears to be a reliable immunohistochemical marker for the discrimination of neoplastic from normal/reactive MCs, with potential as a diagnostic tool in SM.
CD25 therefore appears to be a reliable immunohistochemical marker for the discrimination of neoplastic from normal/reactive MCs, with potential as a diagnostic tool in SM.
C-kit receptor mutations have been identified as causative for CM, some of which potentially respond to imatinib treatment as described for patients with systemic mastocytosis.
TET2 mutations have recently been described in approximately 29% of patients with systemic mastocytosis, but their pathogenetic or treatment relevance is unknown.
ASXL1 but not TET2 mutations adversely impact overall survival of patients suffering systemic mastocytosis with associated clonal hematologic non-mast-cell diseases.
A case of systemic mastocytosis carrying the characteristic mutation at codon 816 (D816V) in the KIT gene of mast cells, with two concurrent accompanying clonal haematopoietic non-mast cell-lineage disorders, chronic myeloproliferative disease, unclassifiable and precursor B lymphoblastic leukaemia is documented.
A high allele burden of the KITD816V mutation in peripheral blood or bone marrow aspirates indicates multi-lineage hematopoietic involvement and has been associated with an aggressive clinical course of systemic mastocytosis.
A pathogenetic mutation, FIP1L1-PDGFRA, that results from an interstitial chromosome 4q12 deletion, leads to a constitutive activation of the platelet-derived growth factor receptor-alpha (PDGFRA) tyrosine kinase as well as a disease phenotype that mimics both the hypereosinophilic syndrome (HES) and systemic mast cell disease associated with eosinophilia (SMCD-eos).
A screen of two independent AML databases (AML<sup>databases</sup>) revealed remarkable similarities between KIT D816<sup>mut</sup>/CBF<sup>neg</sup> SM-AML and KIT D816<sup>mut</sup>/CBF<sup>neg</sup> AML<sup>databases</sup> (n = 69) with regard to KIT D816<sup>mut</sup> variant allele frequency, mutation profile, aberrant karyotype, and OS suggesting underlying SM in a significant proportion of AML<sup>databases</sup> patients.