title: Minichromosome maintenance proteins are useful adjuncts to differentiate between benign and malignant melanocytic skin lesions.
abstract: BACKGROUND
  Markers identifying premalignant and malignant melanocytic skin lesions are needed.
  
  
  OBJECTIVE
  We aimed to investigate the protein expression of minichromosome maintenance (MCM) proteins in melanocytic skin lesions with different malignant potential.
  
  
  METHODS
  Paraffin-embedded sections of benign melanocytic nevi (BN, n = 37), dysplastic nevi (DN, n = 25), and primary superficial spreading (SSM, n = 58) were assessed. Immunohistochemistry was performed for Ki-67, MCM3, MCM4, and MCM7 antibodies.
  
  
  RESULTS
  Ki-67 expression of SSM was significantly increased when compared to DN (P = .0001) and BN (P = .0015). Compared to BN and DN, expression of MCM3 was significantly increased in SSM (P < .0001 and P = .019, respectively). MCM3 expression of DN was significantly increased as compared to BN (P = .0067). There was a significant correlation between MCM3 expression and Breslow tumor thickness (r = 0.44, P = .019). In SSM, MCM4 expression was significantly increased when compared with DN (P < .0001) and BN (P = .0033). MCM4 immunoreactivity was significantly higher in DN than in BN (P = .016). Immunohistology of MCM7 did not reveal significant differences between the groups investigated (P = .48). However, immunoreactivity of MCM7 significantly correlated with Breslow tumor thickness and Clark level (r = 0.39, P = .023; r = 0.44, P = .010, respectively).
  
  
  CONCLUSIONS
  Limitations of our study include the absence of survival data, mRNA results, and functional studies.
  
  
  CONCLUSIONS
  MCM3 as well as MCM4 are differentially expressed in BN, DN, and SSM. Hence, immunolabeling of MCM3 and MCM4 proteins appears to be a promising additive tool for distinguishing benign from malignant melanocytic skin lesions.
authors.affiliation: Department of Dermatology and Allergology, Ruhr-University Bochum, Gudrunstrasse 56, Bochum D-44791, Germany. t.gambichler@klinikum-bochum.de
authors.forename: Thilo
authors.initials: T
authors.lastname: Gambichler
authors.forename: Marina
authors.initials: M
authors.lastname: Shtern
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rotterdam
authors.forename: Falk G
authors.initials: FG
authors.lastname: Bechara
authors.forename: Markus
authors.initials: M
authors.lastname: Stücker
authors.forename: Peter
authors.initials: P
authors.lastname: Altmeyer
authors.forename: Alexander
authors.initials: A
authors.lastname: Kreuter
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis*; D018797:Cell Cycle Proteins / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000032:analysis*; D004416:Dysplastic Nevus Syndrome / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D064126:Minichromosome Maintenance Complex Component 3; D064148:Minichromosome Maintenance Complex Component 4; D064168:Minichromosome Maintenance Complex Component 7; D009508:Nevus, Pigmented / Q000737:chemistry*; D009687:Nuclear Proteins / Q000032:analysis*; D012878:Skin Neoplasms / Q000737:chemistry*
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; C066470:MCM3 protein, human; D009687:Nuclear Proteins; C099243:MCM4 protein, human; C101624:MCM7 protein, human; D064126:Minichromosome Maintenance Complex Component 3; D064148:Minichromosome Maintenance Complex Component 4; D064168:Minichromosome Maintenance Complex Component 7