Isolation of tumor-infiltrating lymphocytes from preserved human tumor tissue specimens for downstream characterization.

Immunophenotyping of tumor-infiltrating lymphocytes (TILs) by flow cytometry can predict clinical efficacy of immunotherapy. However, several obstacles need to be overcome for developing a flow cytometry assay starting from solid tumor specimens. Here, we show a detailed enzyme-based protocol to isolate TILs from human tumor tissues. The protocol was optimized to obtain enough viable TILs from a biopsy tissue specimen for flow cytometry-based TIL immunophenotyping. Additionally, tissue samples could be preserved for up to 72 h for subsequent characterization. For complete details on the use and execution of this protocol, please refer to Kumagai et al. (2020, 2022).