Detection of phospho-STAT5 in mast cells: a reliable phenotypic marker of systemic mast cell disease that reflects constitutive tyrosine kinase activation.
Systemic mastocytosis (SM) is characterized by the abnormal proliferation and accumulation of mast cells (MCs). Constitutive activation of kit, a receptor tyrosine kinase (TK), has been associated with all types of SM. Signal transducers and activators of transcription (STATs), such as STAT5, mediate downstream kit signalling. We hypothesized that nuclear phospho-STAT5 (pSTAT5) in MCs might reflect TK activation and would be a marker of abnormal MCs in SM. Expression of tryptase, CD25, CD2 and pSTAT5 was evaluated by immunohistochemistry (IHC) on archival cases of SM and cutaneous mastocytosis (CM). pSTAT5 was detected in 23/23 of SM and 1/9 of CM MC nuclei. 23/23 SM had CD25 + MCs. Control tissue MCs were negative for pSTAT5. Nuclear pSTAT5 in MCs from SM reflects abnormal TK activation. We propose nuclear pSTAT5 positivity in MCs as an additional minor phenotypic criterion for diagnosis of SM in future World Health Organization classification schemes.
Zuluaga Toro
Tania
T
Department of Clinical Pathology, Cleveland Clinic, Cleveland, OH 44195, USA.
Hsieh
Fred H
FH
Bodo
Juraj
J
Dong
Henry Y
HY
Hsi
Eric D
ED
D000293:Adolescent; D000328:Adult; D000368:Aged; D001483:Base Sequence; D015415:Biomarkers / Q000032:analysis; D001856:Bone Marrow Examination; D018801:CD2 Antigens / Q000032:analysis; D002467:Cell Nucleus / Q000737:chemistry; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis; D008297:Male; D008407:Mast Cells / Q000737:chemistry* / Q000378:metabolism; D034701:Mastocytosis, Cutaneous / Q000201:enzymology; D034721:Mastocytosis, Systemic / Q000175:diagnosis* / Q000201:enzymology; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000032:analysis* / Q000235:genetics; D016415:Sequence Alignment; D019089:Stem Cell Factor / Q000235:genetics; D053802:Tryptases / Q000032:analysis
D015415:Biomarkers; D018801:CD2 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D050799:STAT5 Transcription Factor; D019089:Stem Cell Factor; D011505:Protein-Tyrosine Kinases; D053802:Tryptases