IL2 and neoplasm: After Dr Rosenberg discovered that TILs can be cultured with the aid of the cytokine interleukin (IL)-2 and induced TIL-exhibited cytotoxic activity against melanoma cells in vitro, TILs isolated from tumor samples were studied in the earliest trials of ACT conducted at the surgical branch of the National Cancer Institute (NCI) in 1988 (29, 30).