4-1BB selected tumor infiltrating lymphocytes

4-1BB Selected Tumor Infiltrating Lymphocytes (TILs) is a type of cell-based immunotherapy that uses a patient's own immune cells from the tumor microenvironment to target and kill cancer cells[4][6]. This therapy involves selecting TILs that express the 4-1BB receptor (a member of the tumor necrosis factor family) from the patient's tumor tissue[6]. The process begins with surgically removing tumor tissue from the patient, isolating the naturally infiltrating lymphocytes (particularly T cells), and expanding them in vitro[4][7]. These 4-1BB-expressing TILs are then reinfused back into the patient where they re-infiltrate the tumor to initiate tumor cell lysis[6].