Figure 3.

(A-D) Representative primary tumors stained by immunohistochemistry for B2M and HLA-A. Orange stars depict tumor tissue; green stars depict stroma and blue stars depict normal tissue. (A) Representative case of hepatocellular carcinoma with strong expression of B2M and HLA-A. B2M and HLA-A show a similar pattern of expression. All tumor cells were strongly positive and normal liver tissue and tumor stroma were also positive. (B) Representative case of urothelial carcinoma with complete loss of B2M and HLA-A expression. B2M and HLA-A show a similar pattern of expression. All tumor cells were negative with positive staining in tumor stroma. (C) Representative case of esophageal carcinoma with strong expression of B2M and complete loss of HLA-A. All tumor cells stained strongly positive for B2M with positive staining in tumor stroma and blood vessels. Tumor cells were negative for HLA-A expression although tumor stroma and blood vessels were positive. (D) Representative case of colorectal cancer with complete loss of B2M and moderate expression of HLA-A. All tumor cells were negative for B2M while stromal areas were positive. Tumor cells displayed cytoplasmic staining for HLA-A while some membrane staining was present (red arrows); positive staining in tumor stroma.