IFNG and neoplasm: To determine if the post-REP TILs are potentially functional, we performed in vitro stimulation with phorbol myristate acetate (PMA) and ionomycin (ION), followed by assessment of interferon-γ (IFNγ) production on 15 randomly selected post-REP TILs that either had accompanying autologous primary tumor cells or patient-derived xenograft (PDX) mice implanted with autologous primary tumor tissues.