HLA-A and neoplasm: As EBV-transformed B cell lines have been shown to express the immunoproteasome constituvely [17], we reasoned that if the lack of recognition of homozygous HLA-A*2402 EBV-B cell lines by DP T cell clone was due to their constitutive expression of immunoproteasome, then tumor cells should also lose expression of the epitope after prolonged treatment with IFN-γ.