Article Text
Abstract
Background/aim: Transporter associated protein (TAP) is important for presenting peptides to major histocompatibility complex (MHC) class I molecules. Defects in TAP lead to decreased MHC class I expression. The immunoexpression of human leucocyte antigen (HLA) class I molecules and the TAP1 subunit were studied in primary uveal melanomas and correlated with the cell types and extrascleral extension.
Methods: The HLA class I antigen and TAP1 subunit were analysed by immunoperoxidase staining with monoclonal antibodies on 45 primary uveal melanoma archival specimens. The tumours were divided into two groups—group A: tumours with no extrascleral extension; group B tumours with extrascleral extension/liver metastasis. Immunoanalysis was done by a semiquantitative method.
Results: HLA class I antigen and TAP1 were decreased in 35 of 35 tumours with no extrascleral extension and positive in six of 10 tumours with liver metastasis. Decreased immunoexpression of HLA class I antigen and TAP1 in uveal melanomas with no extrascleral extension was significant (p<0.001). HLA class I antigen and TAP1 were negative in spindle cell melanomas (p<0.001).
Conclusions: HLA class I antigen and TAP1 expression were decreased in uveal melanomas with no extrascleral extension and in spindle cell melanomas. Decreased expression of TAP1 may lead to decreased expression of HLA class I antigen in uveal melanomas. This preliminary observation deserves further investigation, which may shed more light on the immune escape mechanisms of this tumour and thus enable novel therapeutic strategies.
- HLA, human leucocyte antigen
- MHC, major histocompatibility complex
- TAP, transporter associated protein
- cell types
- extrascleral extension
- immunohistochemistry
- transporter associated protein
- uveal melanoma
- HLA, human leucocyte antigen
- MHC, major histocompatibility complex
- TAP, transporter associated protein
- cell types
- extrascleral extension
- immunohistochemistry
- transporter associated protein
- uveal melanoma
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Footnotes
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Commercial relationships: Nil.