STAT1 and cancer: However, during the induction of PD-L1 with anti-cancer compounds, upstream markers of the JAK-STAT1-IRF pathway were absent (Fig. 2B), suggesting that under stressful conditions there is an alternative pathway for PD-L1 expression, similar to an alternative cytokine signaling independent inflammation38.This form of cell stress-related, but not IFN-γ signaling context PD-L1 expression, could be associated with the emerging role of PD-L1 as a cell autonomous factor that is responsible for cancer cell survival and resistance to drug treatment32,39,40.