Immunophenotypic markers to differentiate between benign and malignant melanocytic lesions.
OBJECTIVE
The authors investigated the expression of S100A1, S100A6, S100B, MelanA, and CEA in conjunctival naevi, primary acquired melanosis (PAM), conjunctival melanoma, and uveal melanoma in order to assess their potential usefulness in the pathological differential diagnosis of these entities.


METHODS
Paraffin embedded sections of 18 conjunctival naevi, 14 PAM, 16 conjunctival melanomas, and 20 uveal melanomas were immunostained for S100A1, S100A6, S100B, MelanA, and CEA, and expression was scored semiquantitatively.


RESULTS
Expression of S100A1 differed significantly between conjunctival naevi and conjunctival melanoma, with percentages of positive cells of 30.6% and 71.4%, respectively. Conjunctival melanomas had high average scores for S100A1 and S100B (71.4%, 62.9%, respectively), while uveal melanomas also had high S100A1 but low S100B scores (88.5%, 18.5%, respectively). MelanA was highly variable; naevi and uveal melanoma had higher average scores than conjunctival melanoma. CEA was hardly detectable in all four groups.


CONCLUSIONS
S100A1 seems to be a possible candidate to differentiate conjunctival naevi from conjunctival melanoma. S100B seems to differentiate between uveal melanoma and conjunctival melanoma. However, the study size was small and therefore the data have to be confirmed by others.
Keijser
S
S
Department of Ophthalmology, Leiden University Medical Centre, PO Box 9600, 2300 RC, Leiden, The Netherlands.
Missotten
G S
GS
Bonfrer
J M
JM
de Wolff-Rouendaal
D
D
Jager
M J
MJ
de Keizer
R J W
RJ
D000951:Antigens, Neoplasm / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D002272:Carcinoembryonic Antigen / Q000032:analysis; D018797:Cell Cycle Proteins / Q000032:analysis; D003229:Conjunctival Diseases / Q000175:diagnosis* / Q000276:immunology; D003230:Conjunctival Neoplasms / Q000175:diagnosis / Q000276:immunology; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D058965:MART-1 Antigen; D008545:Melanoma / Q000175:diagnosis / Q000276:immunology; D008548:Melanosis / Q000175:diagnosis / Q000276:immunology; D009363:Neoplasm Proteins / Q000032:analysis; D009414:Nerve Growth Factors / Q000032:analysis; D009506:Nevus / Q000175:diagnosis / Q000276:immunology; D000075383:S100 Calcium Binding Protein A6; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000032:analysis*; D014604:Uveal Neoplasms / Q000175:diagnosis / Q000276:immunology
D000951:Antigens, Neoplasm; D015415:Biomarkers; D002272:Carcinoembryonic Antigen; D018797:Cell Cycle Proteins; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins; D009414:Nerve Growth Factors; D000075383:S100 Calcium Binding Protein A6; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C110294:S100A1 protein; C579160:S100B protein, human; C055351:S100A6 protein, human