STAT3 and breast cancer: Breast cancer samples predicted by these classifiers as having a higher expression of immune response genes (good-prognosis) indeed overexpressed PDL1. Second, we found that the probability of activation [40] of immune-related pathways such as IFNα, IFNγ, STAT3 and TNFα was associated with PDL1 overexpression, both in the whole cohort of samples and in each molecular subtype (data not shown).