Author/Editor		Šekoranja, Daja; Hawlina, Gregor; Pižem, Jože
Title		PRAME expression in melanocytic lesions of the conjunctiva
Type		članek
Publication year		2021
Volume		str. str.
ISSN		0309-0167 - Histopathology
Language		eng
Abstract		Aims: PRAME (PReferentially expressed Antigen in MElanoma) is a tumour-associated antigen that is preferentially strongly expressed in most cutaneous melanomas but not or only focally in nevi. Our aim was to evaluate PRAME expression in melanocytic lesions of the conjunctiva. Methods and results: Surgical specimens of 114 conjunctival melanocytic nevi of different types (including 67 common, 25 combined deep penetrating and 21 inflamed juvenile nevi), 30 invasive melanomas, 10 in situ melanomas, 23 primary acquired melanoses (PAM) without atypia and 11 PAM with atypia were analysed for PRAME expression by immunohistochemistry. Nuclear positivity for PRAME in melanocytes was assessed as the percentage of positive nuclei: negative (0%), 1+ (1-25%), 2+ (26-50%), 3+ (51-75%) and 4+ (>75%). In 113 of 114 conjunctival melanocytic nevi, PRAME was either completely negative or focally 1+ positive. Diffuse 4+ PRAME expression was identified in 17 of 30 (57%) invasive melanomas, 7 of 10 (70%) in situ melanomas, 4 of 5 (80%) PAM with severe atypia, 0 of 3 PAM with moderate atypia, 0 od 3 PAM with mild atypia, 1 of 23 (4%) PAM without atypia and 0 of 114 nevi. Diffuse 4+ PRAME expression in invasive melanomas correlated with a higher mitotic count but was not related to age and gender of the patients, Breslow thickness, location or mutational status. Conclusion: Diffuse 4+ PRAME positivity is highly specific for malignant conjunctival melanocytic lesions. PRAME is therefore a useful ancillary marker to support the diagnosis of a suspected conjunctival melanoma.
Keywords		PRAME melanom nevus PRAME melanoma nevus