Predictors of tumor-infiltrating lymphocyte efficacy in melanoma

In the past decades, the increasing knowledge in cellular immunology and tumor-host immune interactions, led to the development of immunotherapy approaches. Immunotherapy, based on adoptive cell transfer of ex vivo activated and expanded tumor-infiltrating T lymphocytes (TILs), has shown promising clinical results in patients with metastatic melanoma. TIL therapy yields response rates of around 50% and significant survival benefit in refractory melanoma patients, even after failing other immunotherapies, such as checkpoint inhibitors or cytokine-based therapy. Identifying predictors of TIL efficacy and detection of TIL subsets with specific reactivity against the patient's tumor might be an important milestone toward further improvement of clinical responses and prolonged survival.