title: Immunohistochemical dual staining as an adjunct in assessment of mitotic activity in melanoma.
abstract: BACKGROUND
  The mitotic rate was introduced as a major prognostic criterion for the staging of thin (≤1.0 mm) melanoma by the 2009 American Joint Committee on Cancer Staging and Classification (seventh edition). The detection of a single mitotic figure changes the tumor stage in thin melanoma. We sought to address the value of a dual staining to facilitate the determination of the mitotic rate and to assign the mitotic activity to melanocytes.
  
  
  METHODS
  The mitotic rate of melanoma cells was determined by dual phosphohistone-H3 (PHH3)/Melan-A immunohistochemistry. Results were compared with PHH3 staining alone and conventional hematoxylin and eosin (H&E)-stained slides of 15 melanomas with a tumor thickness <1.0 mm.
  
  
  RESULTS
  PHH3 staining clearly labeled cells in the mitotic cell cycle. The mitotic rate in the PHH3/Melan-A dual stain was equal to that derived by H&E staining. Time required for counting mitotic figures was significantly reduced.
  
  
  CONCLUSIONS
  The evaluation of mitotic rate with an immunohistochemical dual stain is faster (mean 63.0%) and more reliable than evaluation by routine H&E staining alone. Dual staining immunohistochemistry may be a useful additional tool to standardize the determination of mitotic rate and may be helpful in evaluation of challenging cases.
authors.affiliation: Kempf and Pfaltz Histological Diagnostics, Zurich, Switzerland.
authors.forename: Kristian
authors.initials: K
authors.lastname: Ikenberg
authors.forename: Madeleine
authors.initials: M
authors.lastname: Pfaltz
authors.forename: Christiane
authors.initials: C
authors.lastname: Rakozy
authors.forename: Werner
authors.initials: W
authors.lastname: Kempf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006657:Histones / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods / Q000592:standards; D058965:MART-1 Antigen / Q000378:metabolism*; D008297:Male; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology*; D008875:Middle Aged; D008938:Mitosis; D009363:Neoplasm Proteins / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods / Q000592:standards
chemical_list: D006657:Histones; D058965:MART-1 Antigen; D009363:Neoplasm Proteins