ABSTRACT
BACKGROUND: In conjunctival melanoma, little is known about the tumour biology and protein-expression patterns. In this study, the authors analysed the expression of the antiapoptotic oncoprotein B cell leukaemia/lymphoma-2 protein (Bcl-2), the tumour-suppressor phosphatase and tensin homologue deleted on chromosome ten (PTEN), and the heat-shock-protein HSP-90 in conjunctival melanoma (CoM) and conjunctival nevi (CoN) by immunohistochemistry (IHC). MATERIAL AND METHODS: IHC was performed on 70 samples of CoM and 12 samples of CoN. Expression patterns between the diagnosis groups were compared. A receiver operating characteristic analysis was performed to determine the diagnostic value of the antigens. RESULTS: HSP-90 (p<0.0001) and PTEN (p=0.001) showed the potential to differentiate between CoM and CoN. Bcl-2 expression was higher in CoM than in CoN (p=0.04). The loss of nuclear PTEN expression was more pronounced in the malignant melanomas than in CoN (p=0.02). Tumours located at unfavourable sites (fornix, palpebral conjunctiva, caruncle) that had developed recurrences expressed almost twice as much HSP-90 than recurrence-free tumours. CONCLUSIONS: Conjunctival melanocytes differentially express Bcl-2, HSP-90 and PTEN, depending on their entity. HSP-90- and PTEN expression may add relevant information for the differentiation between conjunctival melanoma and nevi.
Subject(s)
Conjunctival Neoplasms/metabolism , HSP90 Heat-Shock Proteins/metabolism , Melanoma/metabolism , Neoplasm Proteins/metabolism , Nevus, Pigmented/metabolism , PTEN Phosphohydrolase/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Diagnosis, Differential , Female , Humans , Immunohistochemistry , Male , Middle Aged , Reproducibility of ResultsABSTRACT
BACKGROUND: To analyse the expression of melanoma chondroitin sulfate proteoglycan (MCSP) and the preferentially expressed antigen of melanoma (PRAME) in conjunctival melanoma (CoM), lymph node (LN) metastases of cutaneous melanoma (CM) and conjunctival nevi (CoN) by immunohistology. METHODS: Immunohistology was performed in 70 samples of CoM, 25 of LN metastases of CM and 12 of CoN, and assessed by an immunoreactive score (0-12 points). Statistical analysis was performed to disclose relevant differences in the expression pattern. The diagnostic value of the markers was tested by receiver operating characteristics (ROC) analysis. RESULTS: MCSP and PRAME were expressed at significantly higher levels in CoM and LN metastases of CM than in CoN (p<0.0001). Within CoM, an MCSP expression <9.0 points meant higher risk for recurrences (Cox HR=3.1) and a shorter recurrence-free survival (p=0.002) than an MCSP expression >9.0 points. ROC analysis showed an area under the curve of 91.3% for MCSP (p=0.0002) and 93.8% for PRAME (p<0.0001). CONCLUSIONS: MCSP and PRAME are differentially expressed in conjunctival melanomas and nevi. MCSP might have an impact on the risk for recurrence in being inversely correlated to the event. Both markers have high potential to discriminate CoM from CoN. The results indicate that immunohistological characteristics gain relevance in the assessment of CoM.
