title: Mast cells in infantile haemangioma possess a primitive myeloid phenotype.
abstract: OBJECTIVE
  Recent reports on infantile haemangioma (IH) have demonstrated a primitive population of interstitial cells expressing the embryonic transcription factor, Nanog, with decreasing abundance during involution. In this report we investigated the expression of Nanog on mast cells in all three phases of IH progression.
  
  
  METHODS
  Paraffin-embedded sections of six proliferating, six involuting and six involuted IH lesions were used to investigate the expression of tryptase, Nanog, CD45, CD34 and GLUT-1 by immunostaining.
  
  
  RESULTS
  Mast cells, identified by their expression of tryptase, were located in the interstitium of IH lesions. 93%, 42% and 0% of these tryptase(+) cells also expressed Nanog, in proliferating, involuting and involuted IH, respectively.
  
  
  CONCLUSIONS
  The identification of an abundant population of tryptase(+)/Nanog(+) cells in IH is novel. The relative loss of Nanog expression as IH involutes may be a result of maturation and/or proliferation of these cells. This report supports the primitive nature of IH.
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Tinte
authors.initials: T
authors.lastname: Itinteang
authors.forename: Swee T
authors.initials: ST
authors.lastname: Tan
authors.forename: Jun
authors.initials: J
authors.lastname: Jia
authors.forename: Ryan
authors.initials: R
authors.lastname: Steel
authors.forename: Emma L
authors.initials: EL
authors.lastname: Laing
authors.forename: Helen D
authors.initials: HD
authors.lastname: Brasch
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Day
mesh_terms: D049109:Cell Proliferation; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D018324:Hemangioma, Capillary / Q000201:enzymology / Q000473:pathology*; D018398:Homeodomain Proteins; D006801:Humans; D007223:Infant; D008407:Mast Cells / Q000201:enzymology / Q000473:pathology*; D022423:Myeloid Cells / Q000473:pathology*; D000071317:Nanog Homeobox Protein; D009386:Neoplastic Syndromes, Hereditary / Q000201:enzymology / Q000473:pathology*; D010641:Phenotype; D053802:Tryptases / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D053802:Tryptases
keywords: ANGIOGENESIS; BIOLOGICAL SCIENCES; HISTOPATHOLOGY; TUMOUR BIOLOGY; VASCULAR TUMOURS