TGFB1 and glioblastoma: In addition, TILs from patient GBM-E recognized mutated peptides involved in the TGF-β signaling pathway, which has a poor prognosis in human GBM [20, 27], the ABCA2 cellular protein that is highly expressed in the brain (recognized by CD8+ TILs), as well as LILRB3, which is implicated in fine-tuning the MHC-I-dependent immune response (recognized by CD8+ TILs) [21].