Loss of antigen-processing molecules in primary orbital melanoma.
OBJECTIVE
To study the antigen-processing molecules in primary orbital melanomas and correlate them with the clinicopathological features.


METHODS
Antigen-processing molecules comprising the low molecular weight proteins LMP2 and LMP10, transporter associated with antigen-processing TAP1, the binding protein tapasin and the chaperone protein calnexin were analyzed by immunoperoxidase staining with monoclonal antibodies in three primary orbital melanomas. The results were correlated clinicopathologically.


RESULTS
The three primary orbital melanomas were composed of spindle cells. LMP2, LMP10, TAP1, tapasin and calnexin were heterogeneous in the two cases with no hepatic metastasis and negative in one case with hepatic metastasis.


CONCLUSIONS
Antigen-processing molecules are decreased in orbital melanomas with increasing aggressiveness. This could have important implications for immunotherapy. This preliminary observation deserves further investigation, which may shed more light on the immune escape mechanisms of this tumor and thus make possible novel therapeutic strategies.
Krishnakumar
Subramanian
S
Department of Ocular Pathology, Medical and Vision Research Foundations, Chennai, Sankara Nethralaya, India.
Lakshmi
Sundaram
S
Abhyankar
Dhiraj
D
Biswas
Jyotirmay
J
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000378:metabolism*; D017920:Antiporters / Q000378:metabolism; D037281:Calnexin / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009918:Orbital Neoplasms / Q000378:metabolism*
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D017920:Antiporters; D007136:Immunoglobulins; D026901:Membrane Transport Proteins; C073119:TAP1 protein, human; C107762:tapasin; D037281:Calnexin; C071313:LMP-2 protein; D003546:Cysteine Endopeptidases