CTLA-4 Immunohistochemistry and Quantitative Image Analysis for Profiling of Human Cancers.

There is an important need in immuno-oncology to develop reliable immunohistochemistry (IHC) to assess the expression of CTLA-4 tumor-infiltrating lymphocytes in human cancers and quantify them with image analysis (IA). We used commercial polyclonal and monoclonal antibodies and characterized three chromogenic cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) assays with suitable specificity and sensitivity for use in formalin-fixed, paraffin-embedded (FFPE) tissues. We found variable numbers of CTLA-4 lymphocytes in multiple types of cancer and secondary lymphoid organs (SLOs) and other normal human tissues.