title: C-Kit SCF receptor (CD117) expression and KIT gene mutation in conjunctival pigmented lesions.
abstract: OBJECTIVE
  To investigate the presence of KIT gene mutations and immunoreactivity in 85 conjunctival melanocytic tumours and to clarify the role of KIT as a potential therapeutic target in this group of patients.
  
  
  METHODS
  Eighty-five conjunctival pigmented tumours [27 melanomas, 12 primary acquired melanosis (PAMs) and 46 nevi] were immunostained for KIT. Intensity and pattern of expression were evaluated. Molecular analysis to identify KIT mutations was performed in 15 selected cases (tumour-rich areas >50%). KIT immunostaining score and pattern were statistically related to patients' age, sex, diagnostic category, presence of relapse, disease-free survival, presence of metastases, metastasis-free survival, limbal versus nonlimbal tumour location and thickness of melanomas.
  
  
  RESULTS
  KIT stains were documented in 48% of melanomas, 50% of PAMs and 24% of nevi. The mean score of KIT staining in the melanomas/PAMs group was significantly different from nevi (p = 0.0076). No statistically significant differences were detected between either c-kit immunostaining score or pattern and each of the other clinico-pathologic parameters considered. No KIT gene mutations were detected in melanomas and nevi. A silent mutation/polymorphism in KIT exon 13 was found in one PAM.
  
  
  CONCLUSIONS
  Despite the high level of KIT immunostains in PAMs and melanomas, this parameter seems not to be a good predictor of the presence of molecular mutations. KIT-activating mutations should be considered an uncommon event in this tumour.
authors.affiliation: Department of Medicine (DIMED), Section of Pathology, University of Padova, Padova, ItalyG.B. Bietti Foundation, IRCCS, Roma, ItalyIstituto Oncologico Veneto, IRCCS, Padova, ItalyDepartment of Ophthalmology, University of Padova, Padova, Italy.
authors.forename: Lara
authors.initials: L
authors.lastname: Alessandrini
authors.forename: Raffaele
authors.initials: R
authors.lastname: Parrozzani
authors.forename: Roberta
authors.initials: R
authors.lastname: Bertorelle
authors.forename: Elisa
authors.initials: E
authors.lastname: Valentini
authors.forename: Cinzia
authors.initials: C
authors.lastname: Candiotto
authors.forename: Luciano
authors.initials: L
authors.lastname: Giacomelli
authors.forename: Edoardo
authors.initials: E
authors.lastname: Midena
authors.forename: Stella
authors.initials: S
authors.lastname: Blandamura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003230:Conjunctival Neoplasms / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000235:genetics* / Q000378:metabolism; D008548:Melanosis / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009154:Mutation; D009508:Nevus, Pigmented / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D019009:Proto-Oncogene Proteins c-kit
keywords: KIT expression; KIT mutations; conjunctiva; melanoma; nevus; primary acquired melanosis