Although constitutive activation of RAS/RAF/MEK/ERK, mTOR and p38 pathways can trigger PD-L1 overexpression in cancer cells, PD-L1 expression is usually induced by different pro-inflammatory stimuli by the binding of transcription factors to its promoter, which explains why this protein is especially associated with inflamed tissues, including high infiltrated tumors [49]. The gene discussed is MTOR; the disease is cancer.