title: Reliability of immunostaining using pan-melanoma cocktail, SOX10, and microphthalmia transcription factor in confirming a diagnosis of melanoma on fine-needle aspiration smears.
abstract: BACKGROUND
  Accurate fine-needle aspiration (FNA) diagnosis of metastatic melanoma is of therapeutic and prognostic significance and often requires ancillary studies. To the authors' knowledge, the reliability of immunostaining using a pan-melanoma cocktail, Sry-related HMG-BOX gene 10 (SOX10), and microphthalmia transcription factor (MITF) in confirming a diagnosis of melanoma on FNA smears has not been studied to date.
  
  
  METHODS
  This retrospective study included 50 FNA cases with a definitive diagnosis of melanoma. Twenty-nine cases were epithelioid type (group 1), and 21 cases were predominantly spindle cell type with or without an epithelioid component (group 2). Each case was immunostained using pan-melanoma cocktail, SOX10, and MITF. Staining intensity and the percentage of positive cells were recorded.
  
  
  RESULTS
  The pan-melanoma cocktail was positive in 43 cases (86%), SOX10 was positive in 50 cases (100%), and MITF in 45 cases (90%). SOX10 and MITF demonstrated nuclear staining with stronger and more diffuse staining with less or no background staining compared with pan-melanoma cocktail, which displayed cytoplasmic staining. For pan-melanoma cocktail and SOX10, the detection rates were identical in groups 1 and 2 (86% with pan-melanoma cocktail and 100% with SOX10). For MITF, the detection rate was higher in group 1 compared with Group 2 (93% vs 86%).
  
  
  CONCLUSIONS
  In the current study, SOX10 was found to have the highest overall detection rate, followed by MITF and pan-melanoma cocktail. The pan-melanoma cocktail and SOX10 performed equally well for groups 1 and 2, and MITF had a higher detection rate in group 1. Overall, SOX10 and MITF appeared to be superior to the pan-melanoma cocktail and SOX10 seemed better than MITF in confirming a diagnosis of melanoma on FNA smears.
authors: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors: Jessica
authors: J
authors: Clevenger
authors: Cicily
authors: C
authors: Joseph
authors: Marilyn
authors: M
authors: Dawlett
authors: Ming
authors: M
authors: Guo
authors: Yun
authors: Y
authors: Gong
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D044963:Biopsy, Fine-Needle / Q000379:methods; D015331:Cohort Studies; D003581:Cytodiagnosis / Q000379:methods; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D058965:MART-1 Antigen / Q000032:analysis; D008297:Male; D008545:Melanoma / Q000737:chemistry* / Q000175:diagnosis / Q000473:pathology*; D058950:Melanoma-Specific Antigens / Q000032:analysis; D051739:Microphthalmia-Associated Transcription Factor / Q000032:analysis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055757:SOXE Transcription Factors / Q000032:analysis*; D012878:Skin Neoplasms / Q000737:chemistry* / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D058951:gp100 Melanoma Antigen
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; C548667:MLANA protein, human; D058950:Melanoma-Specific Antigens; D051739:Microphthalmia-Associated Transcription Factor; C548637:PMEL protein, human; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors; D058951:gp100 Melanoma Antigen
keywords: Sry-related HMG-BOX gene 10 (SOX10); cytology; fine-needle aspiration (FNA); melanoma; microphthalmia transcription factor (MITF); pan-melanoma; smear