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Reliability of immunostaining using pan‐melanoma cocktail, SOX10, and microphthalmia transcription factor in confirming a diagnosis of melanoma on fine‐needle aspiration smears
Author(s) -
Clevenger Jessica,
Joseph Cicily,
Dawlett Marilyn,
Guo Ming,
Gong Yun
Publication year - 2014
Publication title -
cancer cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.29
H-Index - 57
eISSN - 1934-6638
pISSN - 1934-662X
DOI - 10.1002/cncy.21458
Subject(s) - microphthalmia associated transcription factor , sox10 , melanoma , medicine , immunostaining , pathology , staining , immunohistochemistry , cancer research , biology , transcription factor , biochemistry , gene
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. Cancer (Cancer Cytopathol) 2014;122:779–785. © 2014 American Cancer Society .