B2M and neoplasm: The expression of class I HLA molecules, which are responsible for antigen presentation to tumor-killing T-cells, including HLA-A, HLA-B, HLA-C, HLA-E, HLA-F, and B2M, was downregulated in 7, 8, 5, 10, 5, and 14 patients, respectively (Figures 8B–H).